1,990 results on '"FERROELECTRICITY"'
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2. Temperature dependent dielectric and ferroelectric properties of Sr2Na(1-x)K(x)Nb5O15 (0≤x≤0.07) Tetragonal Tungsten Bronze (TTB) ceramics
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Riaz, Muhammad Fahad, Hussain, Fayaz, and Chandio, Ali Dad
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- 2025
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3. Improving the thermal stability of 180° domain switching by engineering the ferroelectric/electrode interface
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Jeyaseelan, Antony, Vishwanath, Sujaya Kumar, Yoon, Sukeun, and Kim, Jihoon
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- 2025
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4. Tailoring La doping concentration for superior ferroelectric and energy storage performance in Bi2WO6 thin films
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Ahn, Yoonho and Son, Jong Yeog
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- 2025
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5. Investigating the photodetection performance of self-biased Au/PZT/ FTO and Au/PZT/Au/FTO UV photodetectors
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Ashtar, M., Marwat, M.A., Bentalib, A., Jumah, A.B., Yang, Y., Xue, W., and Cao, D.
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- 2025
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6. Freestanding ferroelectric thin film with robust ferroelectricity via inserted dielectric layers
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Dai, Liyufen, Yao, Dijie, An, Feng, Cheng, Mingqiang, Zhong, Xiangli, Tang, Zhenhua, and Zhong, Gaokuo
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- 2025
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7. Alternating multi-pulse atomic layer deposition for dopant tailoring in sub-10 nm ferroelectric thin films
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Wang, Ting-Yun, Chuang, Chun-Ho, Mo, Chi-Lin, Jiang, Yu-Sen, Shyue, Jing-Jong, Shieh, Jay, and Chen, Miin-Jang
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- 2025
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8. Surface-Induced effects in ferroelectric BaTiO3 thin films
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Kushwaha, Anoop Kumar, Khadka, Rajan, and Keblinski, Pawel
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- 2025
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9. Chemically driven BaTiO3–CoFe2O4 nanocomposite with strong dielectric and low leakagecharacteristics for electrocatalytic water splitting reaction
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Singh, Purnima, Mahato, Anupama, Mondal, Debasish, Panda, Bholanath, Sahis, Amrit, Pramanik, Anup, and Dhak, Debasis
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- 2024
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10. Rapid microwave annealing of ferroelectric copolymer films for multifunctional perception
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Luo, Xingsheng, Yang, Jiang, Feng, Yirou, and Zhu, Guodong
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- 2024
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11. Enhanced magnetoelectric properties of the composite films of Bi0.5Na0.5Ti0.98Fe0.02O3-δ-NiFe1.98Nd0.02O4 with different deposition sequences
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Shi, Min, Du, Shushu, Chen, Wu, Chen, Hao, Xu, Yudong, Zuo, Ruzhong, and Bai, Tiancheng
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- 2024
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12. Phase field theoretical study of the electrocaloric effect in porous ferroelectric films.
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Liu, Zenghong, Xiang, Yuanjin, Zou, Xing, Zhu, Zhe, and Fang, Wenxiao
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PYROELECTRICITY , *ADIABATIC temperature , *FERROELECTRICITY , *CERAMICS , *THIN films , *FERROELECTRIC thin films - Abstract
It has been experimentally observed that changes in the nanopore structure have a great impact on the ferroelectric domain structure, and then, the ferroelectric polarization value of the film can be controlled to increase the response of the electrocaloric effect. This phenomenon has great application prospects in refrigeration applications. In this study, the evolution process of the domain structure of porous ferroelectric films of Pb0.7 Sr0.3TiO3 (PST) with different pore shapes was obtained through phase field simulation, and the influence of the pore shape on the performance of electrocaloric was predicted and analyzed. The results show that different shapes of pores can control the magnitude of the adiabatic temperature change. Among them, the anisometric ellipse shaped pore thin film can obtain a maximum adiabatic temperature change of 8 K, which is a significant improvement compared with traditional PST ceramics and PST non-porous films. This large adiabatic temperature change is due to the pore-induced domain switching. Therefore, controlling the pore shapes provides a new idea for optimizing the electrocaloric properties of porous ferroelectric thin films. [ABSTRACT FROM AUTHOR]
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- 2025
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13. Application of the Skanavi model to CaCu3Ti4O12 materials.
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Luo, Hao, Geng, Kejia, Qin, Xinrui, Kong, Cuncun, Liu, Xin, Su, Xueyan, Su, Yaoheng, Lu, Dingze, and Cheng, Pengfei
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ELECTRIC fields , *FERROELECTRICITY , *PERMITTIVITY , *OCTAHEDRA , *EQUATIONS - Abstract
In this paper, the optical and static permittivities of CaCu3Ti4O12 supercells are calculated based on the Skanavi model by decomposing the electric field of molecules into the electric field of ions. The results show that the Skanavi model's theoretical predictions are significantly more accurate than those of the Clausius–Mossotti equation and Born model and are in good agreement with the experimental data. In addition, the absence of ferroelectricity in CaCu3Ti4O12 is also revealed by investigating the changes in the structural coefficients of the effective electric field caused by the displacement of Ti4+ along the z-axis. Finally, by analyzing the contribution of TiO6 octahedra or CuO4 planar squares to the static permittivity, the main polarization unit in the structure of CaCu3Ti4O12 has been discovered. This study not only makes up for the insufficient research on the polarization mechanism of CaCu3Ti4O12 but also provides a new tool to explore the polarization mechanism of other materials. [ABSTRACT FROM AUTHOR]
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- 2025
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14. Modulation of flux-closure polar state for enhanced storage unit and thermal conductivity via dual-probe excitation.
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Luo, S. S., Hu, S. W., Shan, D. L., Liu, Y. Y., Lei, C. H., and Pan, K.
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NANOFILMS , *PIEZORESPONSE force microscopy , *FERROELECTRIC devices , *FERROELECTRIC materials , *FERROELECTRICITY - Abstract
Ferroelectric topological structures have broad application prospects for high-density information storage for long-term data retention via topological protection. However, the high-density memory component might generate tremendous power consumption, causing the failure of ferroelectric devices due to the severe thermal effect. There remains an emergent issue on the synchronous achievement of high-density data storage with the decreasing influences of the thermal effects in ferroelectric topological domain structures. Here, we introduce dual-probe excitation to control the symmetry of the electric field and integrate the phase field simulation for modulating the flux-closure ferroelectric domain configuration to simultaneously improve the memory storage unit and thermal conductivity at the nanoscale in PbTiO3 thin film under a piezoresponse force microscopy experiment. It is found that the grown flux-closure polar state in both in-plane directions encourages us to enhance the storage density during dual-probe excitation in topological ferroelectric memory devices. Moreover, the increased number of flux-closure polar states and the decreased density of the domain walls can be obtained by using dual-probe excitation. Finally, we figured out that both the double-staircase-like and paddle-like domain configurations exhibit large storage units and effective thermal conductivity simultaneously under dual-probe excitation. Our study gives a guideline to synchronously improve storage performance and thermal conductivity through multiple-probe excitations in topological ferroelectric materials and devices. [ABSTRACT FROM AUTHOR]
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- 2025
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15. General theory of cavity-mediated interactions between low-energy matter excitations.
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Sánchez Martínez, Carlos J., Lindel, Frieder, García-Vidal, Francisco J., and Feist, Johannes
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PROPERTIES of matter , *ELECTROMAGNETIC coupling , *DEGREES of freedom , *SUPERCONDUCTIVITY , *FERROELECTRICITY - Abstract
The manipulation of low-energy matter properties such as superconductivity, ferromagnetism, and ferroelectricity via cavity quantum electrodynamics engineering has been suggested as a way to enhance these many-body collective phenomena. In this work, we investigate the effective interactions between low-energy matter excitations induced by the off-resonant coupling with cavity electromagnetic modes. We extend a previous work by going beyond the dipole approximation accounting for the full polarization and magnetization densities of matter. We further include the often neglected diamagnetic interaction and, for the cavity, we consider general linear absorbing media with possibly non-local and non-reciprocal response. We demonstrate that, even in this general scenario, the effective cavity-induced interactions between the matter degrees of freedom are of electrostatic and magnetostatic nature. This confirms the necessity of a multimode description for cavity engineering of matter systems where the low-energy assumption holds. Our findings provide a theoretical framework for studying the influence of general optical environments on extended low-energy matter excitations. [ABSTRACT FROM AUTHOR]
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- 2024
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16. Harnessing room-temperature ferroelectricity in metal oxide monolayers for advanced logic devices.
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Naseer, Ateeb, Rafiq, Musaib, Bhowmick, Somnath, Agarwal, Amit, and Singh Chauhan, Yogesh
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FERROELECTRIC materials , *FIELD-effect transistors , *VALENCE bands , *LOGIC devices , *FERROELECTRICITY - Abstract
Two-dimensional ferroelectric materials are beneficial for power-efficient memory devices and transistor applications. Here, we predict out-of-plane ferroelectricity in a new family of buckled metal oxide (MO; M: Ge, Sn, Pb) monolayers with significant spontaneous polarization. Additionally, these monolayers have a narrow valence band, which is energetically separated from the rest of the low-lying valence bands. Such a unique band structure limits the long thermal tail of the hot carriers, mitigating subthreshold thermionic leakage and allowing field-effect transistors (FETs) to function beyond the bounds imposed on conventional FETs by thermodynamics. Our quantum transport simulations reveal that the FETs based on these MO monolayers exhibit a large ON/OFF ratio with an average subthreshold swing of less than 60 mV/decade at room temperature, even for short gate lengths. Our work motivates further exploration of the MO monolayers for developing advanced, high-performance memory and logic devices. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Insights into the ferroelectric orthorhombic phase formation in doped HfO2 thin films.
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Wen, Yichen, Wu, Maokun, Cui, Boyao, Wang, Xuepei, Wu, Yishan, Li, Yu-Chun, Ye, Sheng, Ren, Pengpeng, Lu, Hong-Liang, Wang, Runsheng, Ji, Zhigang, and Huang, Ru
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CRITICAL temperature , *THIN films , *DOPING agents (Chemistry) , *FERROELECTRICITY , *TIMEKEEPING - Abstract
Despite the extensive research on HfO2-based thin films, the ferroelectric orthorhombic phase formation remains unclear. This work proposes a physical picture throughout the entire annealing process to describe the phase transition. Subsequently, the phase evolution at various doping and annealing temperatures is illustrated based on a kinetic model formalized from the classical nucleation theory. It is found that the formation of the ferroelectric orthorhombic phase depends not only on a modest doping concentration but also on the thermal activation of the t-to-o phase transition provided by a sufficient annealing temperature. In addition, phase transition rates correlated to the monoclinic phase formation are effectively suppressed by doping. The exploration of combined effects of annealing parameters indicates a more decisive role of the annealing temperature rather than the keeping time for induced ferroelectricity, and the doping impact becomes significant when a critical annealing temperature is reached. This work provides an understanding for exploring the kinetic effect on the phase transition in HfO2-based thin films, which helps improve ferroelectricity in doped HfO2 ferroelectric films. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Ferroelectricity and nanotube-induced synthesis of one-dimensional group-Ⅳ monochalcogenide nanowires
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Guo, Jiasen, Li, Xinxin, Wang, Huijuan, Zhong, Chenghuan, Zheng, Xiaole, Chen, Ying, Yang, Dingyan, Xie, Shimao, and Li, Chunmei
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- 2023
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19. First-principles study of polar magnets corundum double-oxides Mn2FeMO6 (M = W and Mo)
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Ali, Akbar, Elsaeedy, H.I., Ullah, Sami, Ali Khan, Sayed, and Khan, Imad
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- 2022
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20. Ferroelectric proximity effects in two-dimensional FeSeTe.
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Disiena, Matthew N., Pandey, Nilesh, Luth, Christopher, Sloan, Luke, Shattuck, Reid, Singh, Jatin V., and Banerjee, Sanjay K.
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FERROELECTRICITY , *FERROELECTRIC materials , *SUPERCONDUCTING transitions , *PERMITTIVITY , *HYSTERESIS loop - Abstract
Recent studies have shown that proximity effects are able to substantially modulate the superconducting properties of various quasi-two-dimensional layered materials such as FeSe, FeSeTe, NbSe2, and NbS2. Due to their high surface charge concentration and high dielectric constants, ferroelectric materials provide an interesting avenue for inducing proximity effects in layered superconductors. In this study, we explore the interactions between FeSeTe and the two-dimensional ferroelectrics CuInP2S6 and CuInP2Se6. We found that contrary to the normal behavior of FeSeTe, FeSeTe/CuInP2S6, and FeSeTe/CuInP2Se6 heterostructures display a peculiar two-step superconducting transition. Further testing revealed a hysteresis loop in the IV curves of these samples when measured below the critical temperature indicating the presence of disorder and domains within FeSeTe. We conclude that these domains are responsible for the two-step transition in FeSeTe and hypothesize that they are induced by the domain structure of the aforementioned ferroelectric materials. [ABSTRACT FROM AUTHOR]
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- 2024
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21. Phase stability, piezoelectricity, and ferroelectricity in nitride short-period superlattices.
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Zhao, Ling-Xu and Liu, Jian
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PIEZOELECTRICITY , *FERROELECTRICITY , *NITRIDES , *SUPERLATTICES , *HETEROGENEITY - Abstract
Improving piezoelectric and ferroelectric responses of group III-nitrides is desired for their potential applications in the emerging microelectromechanical-based systems. One possible approach to realize the optimization and control of functionalities is to bring together compounds with different properties to form the ordered multilayer superlattices. In this work, we systematically investigate the phase stability, piezoelectricity, and ferroelectricity in a class of wurtzite-structure-derived nitride superlattices with a periodic alternation of chemically and/or structurally different layers. The structural heterogeneity and phase stability of the ordered wurtzite-structure-derived superlattices are intimately related to the ionic radii mismatch between the substitutional compounds and the parent nitrides. Moreover, the internal structural distortion of the nitride superlattices has a crucial impact on the ferroelectricity and piezoelectricity, namely, piezoelectric and ferroelectric responses become increasingly enhanced as the buckled atomic layers becomes flatter. This work offers fundamental physical insights into the structure–property relationships in nitride superlattices and may propose some material design strategies for achieving high-performance materials with desired responses. [ABSTRACT FROM AUTHOR]
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- 2024
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22. Influence of oxygen pressure on the ferroelectricity of pulsed laser deposition fabricated epitaxial Y-doped HfO2.
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Huang, Jia-hao, Yang, Lei, Wei, Lu-qi, Wang, Tao, Fan, Wen-cheng, Qu, Ke, Guan, Zhao, Chen, Bin-bin, Xiang, Ping-hua, Duan, Chun-gang, and Zhong, Ni
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PULSED laser deposition , *ATOMIC layer deposition , *FERROELECTRICITY , *FERROELECTRIC materials , *SPUTTER deposition , *PULSED lasers - Abstract
Ferroelectric properties of hafnium-based thin films have gained significant interest, yet the fundamental mechanisms responsible for the emergence of the ferroelectric phase continue to be inadequately investigated. In contrast with polycrystalline films fabricated by atomic layer deposition or sputter methods, which possess uncertainty in polarization orientation, epitaxial ferroelectric HfO2-based materials are less investigated, especially for factors such as electric field and oxygen vacancy, which are proposed and examined for their potential impacts on phase stability. In this study, Y-doped hafnium oxide (HYO) ferroelectric epitaxial films were fabricated using pulsed laser deposition, with variations in oxygen pressure during the deposition process. Structural and electrical analyses of HYO epitaxial ferroelectric films prepared under differing oxygen pressures revealed a correlation between the ferroelectric properties of the films and the oxygen content. An optimal selection of oxygen pressure was found to be conducive to the formation of HYO epitaxial ferroelectric films, presenting a promising avenue for future ferroelectric memory applications. [ABSTRACT FROM AUTHOR]
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- 2024
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23. Influence of oxygen pressure on the ferroelectricity of pulsed laser deposition fabricated epitaxial Y-doped HfO2.
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Huang, Jia-hao, Yang, Lei, Wei, Lu-qi, Wang, Tao, Fan, Wen-cheng, Qu, Ke, Guan, Zhao, Chen, Bin-bin, Xiang, Ping-hua, Duan, Chun-gang, and Zhong, Ni
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PULSED laser deposition ,ATOMIC layer deposition ,FERROELECTRICITY ,FERROELECTRIC materials ,SPUTTER deposition ,PULSED lasers - Abstract
Ferroelectric properties of hafnium-based thin films have gained significant interest, yet the fundamental mechanisms responsible for the emergence of the ferroelectric phase continue to be inadequately investigated. In contrast with polycrystalline films fabricated by atomic layer deposition or sputter methods, which possess uncertainty in polarization orientation, epitaxial ferroelectric HfO
2 -based materials are less investigated, especially for factors such as electric field and oxygen vacancy, which are proposed and examined for their potential impacts on phase stability. In this study, Y-doped hafnium oxide (HYO) ferroelectric epitaxial films were fabricated using pulsed laser deposition, with variations in oxygen pressure during the deposition process. Structural and electrical analyses of HYO epitaxial ferroelectric films prepared under differing oxygen pressures revealed a correlation between the ferroelectric properties of the films and the oxygen content. An optimal selection of oxygen pressure was found to be conducive to the formation of HYO epitaxial ferroelectric films, presenting a promising avenue for future ferroelectric memory applications. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
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24. Atomic-Scale Scanning of Domain Network in the Ferroelectric HfO2 Thin Film
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Park, Kunwoo, Kim, Dongmin, Lee, Kyoungjun, Lee, Hyun-Jae, Kim, Jihoon, Kang, Sungsu, Lin, Alex, Pattison, Alexander J, Theis, Wolfgang, Kim, Chang Hoon, Choi, Hyesung, Cho, Jung Woo, Ercius, Peter, Lee, Jun Hee, Chae, Seung Chul, and Park, Jungwon
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Macromolecular and Materials Chemistry ,Chemical Sciences ,Engineering ,Physical Sciences ,Materials Engineering ,ferroelectricity ,HfO2 ,grain boundaries ,crystal structure ,domain network ,Nanoscience & Nanotechnology - Abstract
Ferroelectric HfO2-based thin films have attracted much interest in the utilization of ferroelectricity at the nanoscale for next-generation electronic devices. However, the structural origin and stabilization mechanism of the ferroelectric phase are not understood because the film is typically nanocrystalline with active yet stochastic ferroelectric domains. Here, electron microscopy is used to map the in-plane domain network structures of epitaxially grown ferroelectric Y:HfO2 films in atomic resolution. The ferroelectricity is confirmed in free-standing Y:HfO2 films, allowing for investigating the structural origin for their ferroelectricity by 4D-STEM, high-resolution STEM, and iDPC-STEM. At the grain boundaries of -oriented Pca21 orthorhombic grains, a high-symmetry mixed-(R3m, Pnm21) phase is induced, exhibiting enhanced polarization due to in-plane compressive strain. Nanoscale Pca21 orthorhombic grains and their grain boundaries with mixed-(R3m, Pnm21) phases of higher symmetry cooperatively determine the ferroelectricity of the Y:HfO2 film. It is also found that such ferroelectric domain networks emerge when the film thickness is beyond a finite value. Furthermore, in-plane mapping of oxygen positions overlaid on ferroelectric domains discloses that polarization is suppressed at vertical domain walls, while it is active when domains are aligned horizontally with subangstrom domain walls. In addition, randomly distributed 180° charged domain walls are confined by spacer layers.
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- 2024
25. Effect of fabrication parameters on the ferroelectricity of hafnium zirconium oxide films: A statistical study.
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Salcedo, Guillermo A., Islam, Ahmad E., Reichley, Elizabeth, Dietz, Michael, Schubert-Kabban, Christine M., Leedy, Kevin D., Back, Tyson C., Wang, Weisong, Green, Andrew, Wolfe, Timothy, and Sattler, James M.
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HAFNIUM oxide films , *FERROELECTRICITY , *HYDROFLUORIC acid , *ZIRCONIUM oxide , *HAFNIUM oxide - Abstract
Ferroelectricity in hafnium zirconium oxide (Hf1 − xZrxO2) and the factors that impact it have been a popular research topic since its discovery in 2011. Although the general trends are known, the interactions between fabrication parameters and their effect on the ferroelectricity of Hf1 − xZrxO2 require further investigation. In this paper, we present a statistical study and a model that relates Zr concentration (x), film thickness (tf), and annealing temperature (Ta) with the remanent polarization (Pr) in tungsten (W)-capped Hf1 − xZrxO2. This work involved the fabrication and characterization of 36 samples containing multiple sets of metal-ferroelectric-metal capacitors while varying x (0.26, 0.48, and 0.57), tf (10 and 19 nm), and Ta (300, 400, 500, and 600 ° C). In addition to the well-understood effects of x and Ta on the ferroelectricity of Hf1 − xZrxO2, the statistical analysis showed that thicker Hf1 − xZrxO2 films or films with higher x require lower Ta to crystallize and demonstrated that there is no statistical difference between samples annealed to 500 and 600 ° C, thus suggesting that most films fully crystallize with Ta ∼ 500 ° C for 60 s. Our model explains 95% of the variability in the Pr data for the films fabricated, presents the estimates of the phase composition of the film, and provides a starting point for selecting fabrication parameters when a specific Pr is desired. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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26. Advanced first principles-based study using berry polarization and wannier formulation to explore the promising ferroelectric material SnTiO3.
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Belboukhari, Aimad, Benchtia, Mohammed, Bakak, Abderrahim, Jallal, Said El, Koumina, My Abdelaziz, Bentaleb, Khaled Ait, Mezzane, Daoud, and Gagou, Yaovi
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FERROELECTRIC materials , *GEOMETRIC quantum phases , *CHEMICAL bonds , *FERROELECTRICITY , *BERRIES - Abstract
Ferroelectricity is a crucial property for numerous applications and is fundamentally important for exploring a significant class of smart materials. One of the primary objectives of many theoretical approaches is to efficiently predict new promising ferroelectric compounds by gaining deep insights into their behavior, thus optimizing their performance across various shapes, geometries, and scales. Among the most compelling and exciting approaches is the intimate combination of Berry phase and Maximally Localized Wannier formulation. Therefore, our study aims to leverage these theoretical advancements to systematically investigate the electronic, chemical bonding, ferroelectric, and piezoelectric properties of the promising hypothetical bulk system SnTiO3 by comparing it with its isomorph PbTiO3. Subsequently, we will expand our comparison to slab properties, such as the effects of slab thickness on electronic properties, employing the robust Wannier-based Tight Binding model. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. Advanced first principles-based study using berry polarization and wannier formulation to explore the promising ferroelectric material SnTiO3.
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Belboukhari, Aimad, Benchtia, Mohammed, Bakak, Abderrahim, Jallal, Said El, Koumina, My Abdelaziz, Bentaleb, Khaled Ait, Mezzane, Daoud, and Gagou, Yaovi
- Subjects
FERROELECTRIC materials ,GEOMETRIC quantum phases ,CHEMICAL bonds ,FERROELECTRICITY ,BERRIES - Abstract
Ferroelectricity is a crucial property for numerous applications and is fundamentally important for exploring a significant class of smart materials. One of the primary objectives of many theoretical approaches is to efficiently predict new promising ferroelectric compounds by gaining deep insights into their behavior, thus optimizing their performance across various shapes, geometries, and scales. Among the most compelling and exciting approaches is the intimate combination of Berry phase and Maximally Localized Wannier formulation. Therefore, our study aims to leverage these theoretical advancements to systematically investigate the electronic, chemical bonding, ferroelectric, and piezoelectric properties of the promising hypothetical bulk system SnTiO
3 by comparing it with its isomorph PbTiO3 . Subsequently, we will expand our comparison to slab properties, such as the effects of slab thickness on electronic properties, employing the robust Wannier-based Tight Binding model. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
28. Phase transitions in HfO2 probed by first-principles computations.
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Kingsland, Maggie, Lisenkov, S., Najmaei, Sina, and Ponomareva, I.
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PHASE transitions , *LANDAU theory , *ELECTRIC field effects , *DENSITY functional theory , *FERROELECTRICITY , *SPACE groups - Abstract
Ever since ferroelectricity was discovered in HfO 2 , the question of its origin remains controversial. Here, we probe this question using a combination of Landau theory of phase transitions and first-principles computations. In such an approach, the energy landscape associated with the phase transition between cubic and different experimentally demonstrated phases of HfO 2 (tetragonal, monoclinic, orthorhombic Pbca, orthorhombic Pnma, and orthorhombic Pca 2 1) is explored using density functional theory calculations. Computations revealed that stabilization of all but orthorhombic Pbca phase is driven by a single unstable zone-boundary antipolar mode X 2 −. When coupled with zone-center modes (Γ 1 + and Γ 3 +), it stabilizes the tetragonal phase. Coupling with four additional modes (Γ 5 + , X 3 − , X 5 − , X 5 +) results in the monoclinic phase, which is the ground state of the material. If, however, Γ 5 + mode is replaced with Γ 4 − mode, orthorhombic polar phase Pca 2 1 is stabilized. The application of this framework to examine the effect of electric field on the ferroelectric phase of hafnia reveals that the field of 5 MV/cm is capable of stabilizing ferroelectric phase over the monoclinic one at 0 K. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. Scalable ferroelectricity of 20 nm-thick (Al0.8Sc0.2)N thin films sandwiched between TiN electrodes.
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Ota, Reika, Yasuoka, Shinnosuke, Mizutani, Ryoichi, Shiraishi, Takahisa, Okamoto, Kazuki, Kakushima, Kuniyuki, Koganezawa, Tomoyuki, Sakata, Osami, and Funakubo, Hiroshi
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THIN films , *FERROELECTRICITY , *TITANIUM nitride , *ELECTRODES , *GAS mixtures , *ALUMINUM foam , *ZINC oxide films - Abstract
Ferroelectric (Al, Sc)N thin films have the potential for use in low-power memory applications. This study demonstrates the thickness scalability of ferroelectricity down to an approximately 20 nm-thick (Al0.8Sc0.2)N film sandwiched between microfabricable TiN electrodes. The impact of the deposition gas atmosphere during the sputtering process and the top electrode materials on the crystal structures and ferroelectric properties was investigated for 20–30 nm-thick (Al0.8Sc0.2)N thin films deposited on Si substrates covered with a TiN layer by radio frequency magnetron sputtering. The deposition atmosphere did not strongly affect the crystal structures of the 30 nm-thick (Al0.8Sc0.2)N films but significantly affected their ferroelectric properties. The leakage current density decreased for films deposited under pure N2 gas compared to the films deposited under a gas mixture of 0.67Ar + 0.33N2. The ferroelectric properties of 20 nm-thick (Al0.8Sc0.2)N films were changed by the top electrode materials; both the switching electric field and its maximum applicable electric field increased for the TiN top electrodes compared with the Pt top electrodes, improving the saturation characteristics of the remnant polarization (Pr) against the applied electric field. Consequently, the 20 nm-thick (Al0.8Sc0.2)N film sandwiched between the microfabricable TiN top and bottom electrodes showed ferroelectricity without noticeable degradation with decreasing film thickness; the film maintained large Pr values of over 100 μC/cm2 in the temperature range from room temperature to 150 °C. The present data open the door to scalable ferroelectric random-access memories using almost thickness-degradation-free thin (Al, Sc)N films with microfabricable TiN electrodes. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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30. Rate-independent model of ferroelectric materials: finite element and finite difference solution: Rate-independent model of ferroelectric materials: M. F. Alhasadi et al.
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Alhasadi, Mawafag F., Shahsavari, Leila, Sun, Qiao, and Federico, Salvatore
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FINITE difference method , *FINITE differences , *FERROELECTRIC materials , *DERIVATIVES (Mathematics) , *PIEZOELECTRIC materials - Abstract
Ferroelectric materials undergo a phenomenon called domain switching when subjected to electric fields exceeding a critical yielding value: an irreversible polarisation arises, that can be removed only by applying an appropriate electric field in the opposite sense. Under a cyclic electric field, this results in a hysteretic behaviour in the relation between the electric field and the polarisation. The hysteresis loop is a measure of the energy dissipated in the ferroelectric switching process. In this study, we introduce a rate-independent model of ferroelectricity, inspired by small-deformation elastoplasticity models. Analogously to the yielding surface in elastoplasticity, we define the switching surface, the boundary of the domain of the admissible states of the system. States in the interior of the domain are reversible, while states on the surface can be either reversible or irreversible, based on the relation between the electric field and the derivative of the yielding function with respect to the electric field. We solve a two-dimensional benchmark boundary-value problem by applying two numerical methods, Finite Differences and Finite Elements. Our results demonstrate the effectiveness of both methods in capturing the nonlinearities and reproducing the electrical hysteresis loops typical of ferroelectric materials. This work establishes a foundational framework for modelling rate-independent ferroelectricity and paves the way for future research on comprehensive elastoplastic-ferroelectric models for piezoelectric materials. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
31. Improved Ferroelectric Effects and Gate Controllability in Hf0.5Zr0.5O2-Gated InAlGaN/GaN MIS-HEMTs Using ZrO2 Seed Layers: Improved Ferroelectric Effects and Gate Controllability in Hf0.5Zr0.5O2-Gated...: Tien-Han Yu et al
- Author
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Yu, Tien-Han, Chen, Yu-Lin, Tsao, Yi-Fan, Hsu, Chin-Tsai, Lu, Tsan-Feng, and Hsu, Heng-Tung
- Subjects
FERROELECTRICITY ,SEMICONDUCTOR technology ,STRAY currents ,THRESHOLD voltage ,POWER density ,MODULATION-doped field-effect transistors - Abstract
Scaling of GaN high-electron-mobility transistors (HEMTs) frequently leads to increased gate leakage current and increased risk of device breakdown when subjected to high-speed switching, ultimately resulting in a reduction of the maximum drain current and output power density. These issues can be effectively mitigated by incorporating a dielectric layer beneath the gate in HEMTs. This study delves into the performance enhancement of Hf
0.5 Zr0.5 O2 -gated InAlGaN/GaN metal–insulator–semiconductor (MIS) HEMTs that are grown on a ZrO2 seed layer. The implementation of ferroelectric Hf0.5 Zr0.5 O2 (HZO) stacks has been shown to significantly reduce gate leakage current and stabilize threshold voltage shifts. Furthermore, the positive bias transconductance peak shift enhances the overall electrical stability of the device. Our findings underscore the potential of using ferroelectric stacks in InAlGaN/GaN HEMTs to achieve higher efficiency and operational stability. These advancements make Hf0.5 Zr0.5 O2 -gated HEMTs particularly suitable for advanced high-power and high-frequency applications, demonstrating their capacity to deliver superior performance under challenging conditions. The results of this study highlight the critical role of dielectric engineering in optimizing GaN-based devices, paving the way for future innovations in semiconductor technology. [ABSTRACT FROM AUTHOR]- Published
- 2025
- Full Text
- View/download PDF
32. Structural, Magnetic, and Ferroelectric Phase Transitions and Energy Storage Efficiency in Ba1-xLaxTi1-xFexO3 Ceramics.
- Author
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Hoang, T. P., Truong-Son, L. V., Phan, Lien, Nghiem, N. T., Truong-Tho, N., Tiep, N. H., Jabarov, S. H., Tien, D. P. T., Tran, T. A., Dang, N. T., Bich, D. D., and Khan, D. T.
- Subjects
PHYSICAL & theoretical chemistry ,PHASE transitions ,INORGANIC chemistry ,X-ray photoelectron spectroscopy ,ENERGY storage - Abstract
The co-substitution effect of La and Fe ions on structural characterization, ferroelectric and magnetic properties, and energy storage efficiency of multiferroics Ba
1-x Lax Ti1-x Fex O3 (0 ≤ x ≤ 0.20) was systematically studied utilizing a combination of x-ray diffraction, scanning electron microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), ferroelectric, and magnetic measurements. The results show a structural transformation from the P4mm tetragonal phase to the Pm-3m cubic one at x = 0.04, with no hexagonal phase across the entire large doping range, which differs from the results previously reported for BaTiO3 systems doped solely with Fe. The XPS results show single valence states of Ba, La, and Ti ions, alongside a mixed valence state of Fe in the investigated samples. Magnetic measurements indicate that the pristine sample (x = 0) exhibits weak ferromagnetic (FM) phases within a diamagnetic (DM) matrix. At x < 0.10, the FM and DM phases are suppressed while the paramagnetic phase becomes dominant, indicating no interaction between Fe ions and a reduction in lattice intrinsic defects such as O and Ti vacancies. For 0.10 ≤ x ≤ 0.15, Fe ions start to couple with each other, enhancing the ferromagnetism. However, as x = 0.20, the saturation magnetization is significantly reduced, indicating competition between FM and antiferromagnetic interactions between Fe ions. Ferroelectric measurements demonstrate the ferroelectric nature of the lightly doped samples (x ≤ 0.10) and the lossy improper ferroelectric nature of the samples with 0.15 ≤ x ≤ 0.20. The lossy improper ferroelectricity is related to electron hopping between the Fe3+ –Fe4+ interaction pathways. The coercive electric field, remnant polarization, and maximum polarization decrease with the increase of the porosity in the samples. Furthermore, Ba1-x Lax Ti1-x Fex O3 exhibits high energy storage efficiencies of up to ~ 77%. These findings demonstrate an effective way to make efficient energy storage materials through optimizing doping level and morphological properties in BaTiO3 and other ferroelectrics. [ABSTRACT FROM AUTHOR]- Published
- 2025
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33. On the giant deformation and ferroelectricity of guanidinium nitrate.
- Author
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Szafrański, Marek and Katrusiak, Andrzej
- Subjects
ELECTRIC conductivity ,ELECTRIC properties ,INELASTIC neutron scattering ,ANGULAR momentum (Mechanics) ,DIELECTRIC measurements ,FERROELECTRIC thin films ,PERMITTIVITY measurement ,FERROELECTRICITY ,TUNNEL junctions (Materials science) - Abstract
The article in Nature Communications discusses the properties of guanidinium nitrate (GN) and challenges the claims made by Karothu et al. regarding the ferroelectricity and semiconductivity of GN crystals. The authors present evidence from previous studies on the giant deformation, crystal structures, and dielectric properties of GN to refute the new properties claimed by Karothu et al. They conclude that GN does not exhibit ferroelectric properties and is unsuitable for certain applications proposed by Karothu et al. The study was supported by the Adam Mickiewicz University in Poznań and the authors declare no competing interests. [Extracted from the article]
- Published
- 2025
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34. Coupled pyroelectric-photovoltaic effect in 2D ferroelectric α-In2Se3.
- Author
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Uzhansky, Michael, Rakshit, Abhishek, Kalcheim, Yoav, and Koren, Elad
- Subjects
ENERGY harvesting ,SHORT-circuit currents ,THERMAL conductivity ,FERROELECTRICITY ,SOLAR energy - Abstract
Pyroelectric and photovoltaic effects are vital in cutting-edge broadband sensors and solar energy harvesting. Recent advances revealed great potential of the bulk photovoltaic effect in two-dimensional (2D) materials to surpass the Shockley-Queiseer limit. Moreover, the atomic thickness, high thermal conductivity and room-temperature ferroelectricity endow 2D ferroelectrics with a superior pyroelectric response. Herein, we combined direct pyroelectric-photovoltaic measurements in 2D α-In
2 Se3 . The results reveal a gigantic pyroelectric coefficient of ∼30.7 mC/m2 K and a figure of merit of ∼135.9 m2 /C. Moreover, a coupled pyroelectric-photovoltaic effect was demonstrated, where the pyroelectric current follows the temperature derivative, while the short-circuit current follows temperature. Finally, we utilized the intercoupled ferroelectricity of In2 Se3 to realize a non-volatile, self-powered photovoltaic memory operation, demonstrating stable short-circuit current switching with 103 ON-OFF ratio. The coupled pyroelectric-photovoltaic effect, along with reconfigurable photocurrent, pave the way for a novel integrated thermal and optical response, in-memory logic and energy harvesting. [ABSTRACT FROM AUTHOR]- Published
- 2025
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35. Mechanical force-induced interlayer sliding in interfacial ferroelectrics.
- Author
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Guan, Zhao, Wei, Lu-qi, Fan, Wen-cheng, Sun, Yi-chen, Cao, Wei, Tian, Ming, Wan, Neng, Tong, Wen-yi, Chen, Bin-bin, Xiang, Ping-hua, Duan, Chun-gang, and Zhong, Ni
- Subjects
FERROELECTRICITY ,FERROELECTRIC crystals ,TRIANGLES ,SUPERLATTICES - Abstract
Moiré superlattices in two-dimensional stacks have attracted worldwide interest due to their unique electronic properties. A typical example is the moiré ferroelectricity, where adjacent moirés exhibit opposite spontaneous polarization that can be switched through interlayer sliding. However, in contrast to ideal regular ferroelectric moiré domains (equilateral triangles) built in most theoretical models, the unavoidable irregular moiré supercells (non-equilateral triangles) induced by external strain fields during the transfer process have been given less attention. Manipulation of controllable polarization evolutions is also a big challenge due to an interlinked network of polarized domains. In this study, we employ a sliding-disturb measurement to examine and modulate these irregular moirés via mechanical force. By introducing a curved substrate, the irregular moirés are fabricated, and three distinct types of moiré domains with different patterns are identified and modulated by external mechanical force disturbing. They exhibit reduced pinning forces when the shear direction is not aligned with the strain direction. The shift of the moirés is observed to be orthogonal to the shear direction. This work offers an effective pathway for the controlled switch of the polarization in interfacial ferroelectricity. Manipulation of controllable polarization evolutions is a big challenge. The authors fabricate the irregular moirés, identifying three distinct types of moiré domains with different patterns, modulating them by external mechanical force disturbing. [ABSTRACT FROM AUTHOR]
- Published
- 2025
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- View/download PDF
36. Quantifying the pyroelectric and photovoltaic coupling series of ferroelectric films.
- Author
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Hu, Chaosheng, Liu, Xingyue, Dan, Huiyu, Guo, Chong, Zhang, Maoyi, Bowen, Chris R., and Yang, Ya
- Subjects
PHOTOVOLTAIC effect ,ENERGY harvesting ,FERROELECTRICITY ,REFERENCE sources ,PERFORMANCE theory - Abstract
The coupling of photovoltaic and pyroelectric effects is a common phenomenon in ferroelectric films and often results in coupling enhancements. Although the coupling effects of a variety of ferroelectric films have been examined in terms of improved performance, they have yet to be quantitatively ranked and assessed. Here, by taking the charge coupling factor, the Yang's charge, and output energy as metrics to evaluate the coupling performance, a methodology is developed for evaluating the performance of a range ferroelectric films when the pyroelectric and photovoltaic effects are coupled. By experimentally measuring and quantitatively ranking the evaluation metrics, the influence of coupling effects on the output charge and the energy harvesting capabilities of various ferroelectric films can be readily visualized. In addition, the analysis of the underlying reasons for the coupling enhancement enables optimization of the methods to quantify the charge coupling factor. This work provides a unique reference for the selection of materials, optimization of performance, and energy harvesting for coupled ferroelectric film-based generators. The Yang's charge is proposed as a metric for evaluating the coupling performance in this study. Compared to the conventional charge coupling factor which only considers the relative performance change, the Yang's charge also considers the absolute performance of the device. [ABSTRACT FROM AUTHOR]
- Published
- 2025
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- View/download PDF
37. Two-Dimensional Ferroelectric Materials: From Prediction to Applications.
- Author
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Jiang, Shujuan, Wang, Yongwei, and Zheng, Guangping
- Subjects
- *
FERROELECTRIC materials , *FERROELECTRIC crystals , *NONLINEAR optics , *FERROELECTRICITY , *CURIE temperature , *FERROELECTRIC devices - Abstract
Ferroelectric materials hold immense potential for diverse applications in sensors, actuators, memory storage, and microelectronics. The discovery of two-dimensional (2D) ferroelectrics, particularly ultrathin compounds with stable crystal structure and room-temperature ferroelectricity, has led to significant advancements in the field. However, challenges such as depolarization effects, low Curie temperature, and high energy barriers for polarization reversal remain in the development of 2D ferroelectrics with high performance. In this review, recent progress in the discovery and design of 2D ferroelectric materials is discussed, focusing on their properties, underlying mechanisms, and applications. Based on the work discussed in this review, we look ahead to theoretical prediction for 2D ferroelectric materials and their potential applications, such as the application in nonlinear optics. The progress in theoretical and experimental research could lead to the discovery and design of next-generation nanoelectronic and optoelectronic devices, facilitating the applications of 2D ferroelectric materials in emerging advanced technologies. [ABSTRACT FROM AUTHOR]
- Published
- 2025
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- View/download PDF
38. A ferroelectric helical polymer.
- Author
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Bandyopadhyay, Supriya, Barman, Shubhankar, Paul, Swadesh, Datta, Anuja, and Ghosh, Suhrit
- Subjects
- *
HYSTERESIS loop , *FERROELECTRICITY , *CHROMOPHORES , *TEMPERATURE - Abstract
This communication introduces helical polyacetylene (P1) with an appended acceptor (A)–donor (D)–acceptor (A) conjugated chromophore as a promising ferroelectric candidate. The helical conformation of P1 leads to a highly stable chiral assembly of the appended ADA chromophores. This results in prominent ferroelectricity as evident from the superior hysteresis loop at room temperature, exhibiting a saturation polarization (PS) value ∼2 μC cm−2 and remanent polarization (Pr) value ∼1.8 μC cm−2 at a low coercive field (Ec) of 5.2 kV cm−1, rarely reported before for purely organic systems. [ABSTRACT FROM AUTHOR]
- Published
- 2025
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- View/download PDF
39. A bulk photovoltaic effect in a zero-dimensional room-temperature molecular ferroelectric [C8N2H22]1.5[Bi2I9].
- Author
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Zhibo Chen, Tianhong Luo, Jinrong Wen, Zhanqiang Liu, Jingshan Hou, Yongzheng Fang, and Ganghua Zhang
- Subjects
- *
PHOTOELECTRIC devices , *OPEN-circuit voltage , *SHORT-circuit currents , *HYSTERESIS loop , *FERROELECTRICITY , *PHOTOVOLTAIC effect , *OPTOELECTRONIC devices - Abstract
Non-toxic molecular ferroelectrics have attracted significant interest due to their unique flexibility, low costs, and environmental friendliness. However, such materials with narrow bandgaps and ferroelectricity above room temperature (RT) are still scarce. Herein, we present a brand-new lead-free molecular ferroelectric [C8N2H22]1.5[Bi2I9] synthesized hydrothermally. [C8N2H22]1.5[Bi2I9] features a zero-dimensional (0D) structure with a polar space group of Pc, as confirmed by single-crystal X-ray diffraction and second-harmonic generation (SHG) analyses. The RT hysteresis loop reveals the intrinsic ferroelectricity of [C8N2H22]1.5[Bi2I9] with a spontaneous polarization (Ps) of 1.3 μC cm−2. A visible-light optical bandgap has been confirmed by UV-vis spectroscopy and theoretical calculations. A notable ferroelectric photovoltaic (PV) effect has been revealed in [C8N2H22]1.5[Bi2I9]-based photoelectric devices with an open-circuit voltage (Voc) of 0.39 V and a short-circuit current density (Jsc) of 2.3 μA cm−2 under AM 1.5G illumination. The PV performance can be significantly enhanced by tuning the ferroelectric polarization, achieving a maximum Voc of 0.47 V and Jsc of about 50 μA cm−2. This study offers a novel member of the 0D lead-free hybrid organic–inorganic molecular ferroelectric family possessing great promise for optoelectronic devices. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
40. Heterojunction Ferroelectric Materials Enhance Ion Transport and Fast Charging of Polymer Solid Electrolytes for Lithium Metal Batteries.
- Author
-
Shan, Jiayao, Gu, Rong, Xu, Jinting, Gong, Shuaiqi, Guo, Shuainan, Xu, Qunjie, Shi, Penghui, and Min, YuLin
- Subjects
- *
PIEZOELECTRICITY , *SOLID electrolytes , *FERROELECTRIC materials , *POLYELECTROLYTES , *FERROELECTRICITY , *FERROELECTRIC ceramics , *SUPERIONIC conductors - Abstract
Solid polymer electrolytes offer great promise for all‐solid‐state batteries, but their advancement is constrained due to the low ionic conductivity at ambient temperature and non‐uniform ion transport, which hampers fast‐charging capabilities. In this study, a ferroelectric heterojunction composite is incorporated into poly(vinylidene difluoride) (PVDF) based solid electrolytes to establish an interfacial electric field that enhances lithium salt dissociation and promotes uniform ion deposition. Electrospun 1D BaTiO3 nanofibers serve as a long‐range organic/inorganic (polymer/filler) interface for ion transport, while MoSe2 hydrothermally grown on BaTiO3 forms Li2Se‐rich high‐speed ion conductors. The piezoelectric effect of the ferroelectric material helps suppress lithium dendrite growth by reversing internal charges and reducing local overpotentials. Consequently, the PVBM electrolyte achieves a substantia ionic conductivity of 6.5 × 10−4 S cm−1 and a Li‐ion transference number of 0.61 at 25 °C. The LiFePO4/PVBM/Li solid‐state batteries demonstrate an initial discharge capacity of 146 mAh g−1 at 1 C, with a capacity preservation of 80.2% upon completion of 1200 cycles, and an initial discharge capacity of 110.7 mAh g−1 at 5 C. These findings highlight the prospect of ferroelectric ceramic fillers to significantly improve ion transport and fast‐charging performance in polymer electrolytes. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
41. Cluster sliding ferroelectricity in trilayer Quasi-Hexagonal C60.
- Author
-
Wang, Xuefei, Ren, Yanhan, Qiu, Shi, Zhang, Fan, Li, Xueao, Gao, Junfeng, Gao, Weiwei, and Zhao, Jijun
- Subjects
POLARIZATION (Electricity) ,BAND gaps ,CHEMICAL bonds ,FERROELECTRICITY ,FERROELECTRIC crystals - Abstract
Electric polarization typically originates from non-centrosymmetric charge distributions in compounds. In elemental crystalline materials, chemical bonds between atoms of the same element favor symmetrically distributed electron charges and centrosymmetric structures, making elemental ferroelectrics rare. Compared to atoms, elemental clusters are intrinsically less symmetric and can have various preferred orientations when they are assembled to form crystals. Consequently, the assembly of clusters with different orientations tends to break the inversion symmetry. By exploiting this concept, we show that sliding ferroelectricity naturally emerges in trilayer quasi-hexagonal phase (qHP) C
60 , a cluster-assembled carbon allotrope recently synthesized. Compared to many metallic or semi-metallic elemental ferroelectrics, trilayer qHP C60 's have sizable band gaps and several ferroelectric structures, which are distinguishable by measuring their second-harmonic generation (SHG) responses. Some of these phases show both switchable out-of-plane and in-plane polarizations on the order of 0.2 pC/m. The out-of-plane and in-plane polarizations can be switched independently and enable an easy-to-implement construction of Van der Waals homostructures with ferroelectrically switchable chirality. [ABSTRACT FROM AUTHOR]- Published
- 2025
- Full Text
- View/download PDF
42. A bulk photovoltaic effect in a zero-dimensional room-temperature molecular ferroelectric [C8N2H22]1.5[Bi2I9].
- Author
-
Zhibo Chen, Tianhong Luo, Jinrong Wen, Zhanqiang Liu, Jingshan Hou, Yongzheng Fang, and Ganghua Zhang
- Subjects
PHOTOELECTRIC devices ,OPEN-circuit voltage ,SHORT-circuit currents ,HYSTERESIS loop ,FERROELECTRICITY ,PHOTOVOLTAIC effect ,OPTOELECTRONIC devices - Abstract
Non-toxic molecular ferroelectrics have attracted significant interest due to their unique flexibility, low costs, and environmental friendliness. However, such materials with narrow bandgaps and ferroelectricity above room temperature (RT) are still scarce. Herein, we present a brand-new lead-free molecular ferroelectric [C
8 N2 H22 ]1.5 [Bi2 I9 ] synthesized hydrothermally. [C8 N2 H22 ]1.5 [Bi2 I9 ] features a zero-dimensional (0D) structure with a polar space group of Pc, as confirmed by single-crystal X-ray diffraction and second-harmonic generation (SHG) analyses. The RT hysteresis loop reveals the intrinsic ferroelectricity of [C8 N2 H22 ]1.5 [Bi2 I9 ] with a spontaneous polarization (Ps ) of 1.3 μC cm−2 . A visible-light optical bandgap has been confirmed by UV-vis spectroscopy and theoretical calculations. A notable ferroelectric photovoltaic (PV) effect has been revealed in [C8 N2 H22 ]1.5 [Bi2 I9 ]-based photoelectric devices with an open-circuit voltage (Voc ) of 0.39 V and a short-circuit current density (Jsc ) of 2.3 μA cm−2 under AM 1.5G illumination. The PV performance can be significantly enhanced by tuning the ferroelectric polarization, achieving a maximum Voc of 0.47 V and Jsc of about 50 μA cm−2 . This study offers a novel member of the 0D lead-free hybrid organic–inorganic molecular ferroelectric family possessing great promise for optoelectronic devices. [ABSTRACT FROM AUTHOR]- Published
- 2025
- Full Text
- View/download PDF
43. Investigating the Interplay of Polar Nanodomains and Superconductivity in Doped Strontium Titanate through Transmission Electron Microscopy.
- Author
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Salmani-Rezaie, Salva
- Abstract
The simultaneous presence of itinerant carriers and polar crystal distortions poses a persistent challenge, especially in polar superconductors such as doped strontium titanate (SrTiO3). This study employs scanning transmission electron microscopy (STEM) to investigate the interplay between ferroelectricity and superconductivity in SrTiO3. Contrary to conventional models, the ferroelectric transition in strained, undoped SrTiO3 exhibits pronounced order-disorder characteristics. Increasing carrier concentration disrupts polar nanodomains, with dopant atoms contributing to the suppression of the ferroelectric transition. The destruction of the global ferroelectric state correlates with the suppression of superconductivity in strained SrTiO3 films, emphasizing the essential role of polar order. The length scale of polar order emerges as a crucial parameter controlling superconductivity in SrTiO3, providing valuable insights into the competition between itinerant carriers and polar crystal distortions. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
44. 1D Crystalline Assemblies Exhibiting Large Second Harmonic Generation Susceptibilities and Stacking‐/Polarization‐Driven Tunability.
- Author
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Yang, Jingyu, Pan, Jinbo, Zhang, Yan‐Fang, Wan, Guolin, Zhu, Yongqian, Wei, Zixuan, Li, Yuhui, and Du, Shixuan
- Subjects
- *
SECOND harmonic generation , *POLARIZATION (Electricity) , *NONLINEAR optics , *DATABASES , *FERROELECTRICITY - Abstract
Nonlinear optical (NLO) van der Waals (vdW) crystals containing 1D building blocks exhibit large NLO coefficients and birefringence that are crucial for their applications. In this work, 21 NLO 1D building blocks with large second harmonic generation (SHG) susceptibility from the Computational 1D Materials Database (C1DB) are screened. Among them, 14 are hitherto unreported and have SHG susceptibilities approaching theoretical upper limits. Forty‐five new vdW NLO crystals are then constructed by stacking one or two of the 21 building blocks. Eighteen of them inherit the large SHG susceptibilities of their corresponding 1D building blocks. Three stable crystals exhibit large SHG susceptibilities and birefringence, while one stable crystal possesses ferroelectricity. Interestingly, the SHG susceptibilities of the newly constructed NLO crystals are inversely proportional to the third power of their bandgaps. Further calculations show that the SHG susceptibilities of the vdW NLO crystals can be tuned either by stacking order or by reversing electric polarization, providing possibilities for their application in tunable nonlinear optics and NLO switches. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
45. 2D Ferroelectric Metal–Organic Frameworks for Ultralow Power Field Effect Transistors.
- Author
-
Xian, Zhenhui, Li, Changjian, Dong, Yangda, Peng, Mengping, Yu, Ye, Zhang, Yuan, Huang, Boyuan, Zhong, Gaokuo, Xie, Shuhong, and Li, Jiangyu
- Subjects
- *
FIELD-effect transistors , *FERROELECTRICITY , *NONVOLATILE memory , *FERROELECTRIC crystals , *NANOSTRUCTURED materials - Abstract
2D ferroelectrics open a new realm of nonvolatile memory and computing devices, while metal–organic frameworks (MOF) offer tremendous possibilities to design and optimize ferroelectric performance. Integrating a MOF ferroelectric gate with a semiconducting channel provides new strategy toward ultralow power ferroelectric field effect transistors (FeFETs), yet no 2D MOF is experimentally demonstrated to be ferroelectric yet. Here, the study successfully develops 2D ferroelectric MOF nanosheets, {CuL2(H2O)2(NO3)2(H2O)1.5·(CH3OH)}∞ wherein L denotes PhPO(NH4Py)2, abbreviated as {CuIIL2}n‐MOF, and confirm its ferroelectricity down to 7 nm thickness. A large polarization of ≈14.2 µC cm−2, small coercive field of ≈33.3 V µm−1, and excellent endurability >106 cycles are found in 2D {CuIIL2}n‐MOF nanosheets. This enables to fabricate FeFETs using 2D {CuIIL2}n‐MOF as the gate and MoS2 as the channel, achieving an on/off ratio of 107 with ultralow off‐state current of 100 fA and tunable memory window, making it exceptional among known FeFETs and very promising for next‐generation ultralow power memories and computing devices [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
46. Discovery of a layered multiferroic compound Cu1-xMn1+ySiTe3 with strong magnetoelectric coupling.
- Author
-
De, Chandan, Yu Liu, Ayyagari, Sai Venkata Gayathri, Boyang Zheng, Kelley, Kyle P., Hazra, Sankalpa, Jingyang He, Pawledzio, Sylwia, Mali, Subin, Guchaait, Samaresh, Suguru Yoshida, Yingdong Guan, Seng Huat Lee, Sretenovic, Milos, Xianglin Ke, Le Wang, Engelhard, Mark H., Yingge Du, Weiwei Xie, and Xiaoping Wang
- Subjects
- *
POLARIZATION (Electricity) , *TRANSITION metal chalcogenides , *REMANENCE , *MAGNETIC hysteresis , *FERROELECTRICITY , *MULTIFERROIC materials - Abstract
Multiferroic materials host both ferroelectricity and magnetism, offering potential for magnetic memory and spin transistor applications. Here, we report a multiferroic chalcogenide semiconductor Cu1-xMn1+ySiTe3 (0.04 ≤ x ≤ 0.26; 0.03 ≤ y ≤ 0.15), which crystallizes in a polar monoclinic structure (Pm space group). It exhibits a canted antiferromagnetic state below 35 kelvin, with magnetic hysteresis and remanent magnetization under 15 kelvin. We demonstrate multiferroicity and strong magnetoelectric coupling through magnetodielectric and magnetocurrent measurements. At 10 kelvin, the magnetically induced electric polarization reaches ~0.8 microcoulombs per square centimeter, comparable to the highest value in oxide multiferroics. We also observe possible room-temperature ferroelectricity. Given that multiferroicity is very rare among transition metal chalcogenides, our finding sets up a unique materials platform for designing multiferroic chalcogenides. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
47. Impact of enhanced ferroelectric polarization through La doping on photovoltaic properties of BiFeO3 thin films on HOPG.
- Author
-
Ahn, Yoonho and Son, Jong Yeog
- Subjects
- *
THIN films , *PYROLYTIC graphite , *BAND gaps , *SURFACE structure , *FERROELECTRIC thin films , *FERROELECTRICITY - Abstract
BiFeO3 (BFO) thin films are well‐known for their multiferroic and photovoltaic properties, driving extensive research into potential applications. Highly ordered pyrolytic graphite (HOPG) substrates, with a graphene‐like surface structure, provide an ideal platform for assessing the impact of graphene electrodes. This study investigates the photovoltaic properties of ITO/BFO/HOPG devices with La‐doped BFO thin films at concentrations of 5, 10, and 15 mol%. The polycrystalline BFO thin films exhibited a preferential (111) orientation, with the 10 mol% La‐doped thin films demonstrating optimal crystallinity and the highest remanent polarization of 50.8 µC/cm2. Photovoltaically, the 5 mol% La‐doped BFO thin film exhibited an open‐circuit voltage (
V oc) of 0.46 V and the highest short‐circuit current (J sc) of 0.38 mA/cm2. The 10 mol% La‐doped BFO thin film achieved the highestV oc of 0.57 V with aJ sc of 0.35 mA/cm2, likely because of enhanced ferroelectric polarization. In contrast, the 15 mol% La‐doped BFO thin film showed a reduced band gap but diminished photovoltaic performance. The minimal variation in the band gap (within 0.1 eV) suggests that the improved photovoltaic performance is primarily driven by increased polarization resulting from enhanced tetragonality. [ABSTRACT FROM AUTHOR]- Published
- 2025
- Full Text
- View/download PDF
48. α-In2Se3/PtX2(X=S,Se,Te)异质结电子结构调控研究.
- Author
-
韩善成, 李京杰, 王楠, 黄火林, and 郝松
- Subjects
BAND gaps ,SMART devices ,FERROELECTRIC materials ,ELECTRONIC equipment ,ENERGY bands - Abstract
Copyright of Journal of Dalian University of Technology / Dalian Ligong Daxue Xuebao is the property of Journal of Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2025
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- View/download PDF
49. Study of Di-/Ferro-/Piezoelectric Properties of Sm3+-Doped ZnO Nanoparticles.
- Author
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Verma, Radha, Goel, Sahil, Verma, Komal, Kant, Krishan, Kumar, Rajesh, Garg, Maneesha, and Gupta, Rashi
- Subjects
DIELECTRIC loss ,STRAY currents ,PERMITTIVITY ,STRAINS & stresses (Mechanics) ,ENERGY density - Abstract
Pristine ZnO and Sm-doped ZnO nanoparticles were synthesized using a wet chemical co-precipitation technique. The morphological and structural characteristics of pristine and Sm-doped ZnO were studied by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques. Increases in lattice parameters, interplanar spacing, and volume was observed from the XRD patterns compared to its JCPDS card. Crystallite size, dislocation density, deformation stress, lattice strain, and energy density for both pristine and Sm-ZnO nanoparticles were calculated using Scherrer and Williamson–Hall (W–H) methods. An energy bandgap reduction was observed in the Sm-doped ZnO (E
g ~ 2.7 eV), which played a crucial role in explaining the increased leakage currents in Sm-ZnO. The Sm-doped ZnO nanoparticles exhibited a remnant polarization (Pr ~ 0.163 µC/cm2 ) and a coercive field (Ec ~ 25.33 kV/cm). Current–voltage (I–V) characteristics show maximum current generated on applying varying voltages (Vmax = 40 V, Imax = ~600 μA). Frequency- and temperature-dependent dielectric studies were conducted to examine the change in the values of the dielectric constant and dielectric loss with the variation in frequency and temperature. The Sm-doped ZnO-based nanogenerator generated an output voltage ~ 400 mV at tapping force of ~ 0.02 kgf, which makes it a prominent candidate for self-powered devices. [ABSTRACT FROM AUTHOR]- Published
- 2025
- Full Text
- View/download PDF
50. Ambient Moisture‐Induced Self Alignment of Polarization in Ferroelectric Hafnia.
- Author
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Wei, Lu‐Qi, Guan, Zhao, Tong, Wen‐Yi, Fan, Wen‐Cheng, Mattursun, Abliz, Chen, Bin‐Bin, Xiang, Ping‐Hua, Han, Genquan, Duan, Chun‐Gang, and Zhong, Ni
- Subjects
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FERROELECTRIC materials , *FERROELECTRICITY , *ELECTRONIC equipment , *ELECTRIC fields , *FERROELECTRIC crystals - Abstract
The discovery of nanoscale ferroelectricity in hafnia (HfO2) has paved the way for next generation high‐density, non‐volatile devices. Although the surface conditions of nanoscale HfO2 present one of the fundamental mechanism origins, the impact of external environment on HfO2 ferroelectricity remains unknown. In this study, the deleterious effect of ambient moisture is examined on the stability of ferroelectricity using Hf0.5Zr0.5O2 (HZO) films as a model system. It is found that the development of an intrinsic electric field due to the adsorption of atmospheric water molecules onto the film's surface significantly impairs the properties of domain retention and polarization stability. Nonetheless, vacuum heating efficiently counteracts the adverse effects of water adsorption, which restores the symmetric electrical characteristics and polarization stability. This work furnishes a novel perspective on previous extensive studies, demonstrating significant impact of surface water on HfO2‐based ferroelectrics, and establishes the design paradigm for the future evolution of HfO2‐based multifunctional electronic devices. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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