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Interface coupling is considered as an effective approach to manipulate the physical properties of heterostructures. Here, we fabricated the heterostructure composed of two-dimensional (2D) ferromagnetic Fe3GeTe2 (FGT) and VI3. The experimental findings demonstrated that VI3 plays a pivotal role in modulating the spin texture of FGT through close-range coupling, leading to a substantial increment in the coercive field (HC) of FGT by ∼150%. To rational our findings, density functional theory calculations were employed to investigate the underlying mechanism. We propose that the spin pining effect at the interface contributes significantly to the observed enhancement of magnetic anisotropy. This research expands our understanding of interface effects and offers a promising method for the magnetism manipulation in 2D ferromagnetic systems. [ABSTRACT FROM AUTHOR]

Unique quantum states induced by disorders can be characterized by quantum phase transitions in many-body systems. In this study, we experimentally observed a sharp resistance peak near the superconducting transition in superconductor/ferroelectric TiN/Hf0.5Zr0.5O2 heterostructures. The peak is attributed to the disorder introduced by ferroelectric fluctuations within the empirical model of metal–boson insulator–superconductor transitions. By modulating the quantum phase transitions in superconductivity and competing with the disorder through ferroelectric polarization, we provide a versatile platform for investigating the influence of ferroelectric materials on superconducting states. [ABSTRACT FROM AUTHOR]

Quantum corrections to conductivity, which reflect charge carriers' quantum behavior, are a significant topic in condensed state physics and device design. A resistivity upturn at low temperature or weak antilocalization due to quantum corrections has been often observed experimentally. However, the coexistence of the low-temperature resistivity upturn and weak antilocalization from quantum corrections in bulk single crystals is seldom reported. Here, we report the transport properties of bulk Ta1.04Ru0.78Te4 single crystals. The samples showed a metallic behavior with a resistivity upturn below ∼8.6 K, which may be the result of quantum correction to the resistivity. The magnetic field enhances the upturn feature. The weakly nonlinear Hall resistivity with a positive slope suggests a p-type and multiband feature for bulk Ta1.04Ru0.78Te4; the electron and hole concentrations and mobilities of the samples are very close to each other and have the same order of magnitude. The Ta1.04Ru0.78Te4 single crystals displayed small and positive magnetoresistance, and the 3 K magnetoresistance at 9 T was about 15%. A lack of overlap of Kohler's plot curves at different temperature implies the violation of Kohler's rule. At low temperature, the dip-like magnetoresistance at low field strengths suggests a weak antilocalization in the Ta1.04Ru0.78Te4 single crystal. A small phase coherence length implies weakened screening and enhancing electron–electron interaction effects. These results reveal the quantum transport properties of Ta1.04Ru0.78Te4 single crystals, which can be considered in the future device design. [ABSTRACT FROM AUTHOR]

SrIrO3 (SIO) with a perovskite structure exhibits broad application prospects in electronic synapses due to its high carrier mobility, scalability, and compatibility with silicon technology. On the other hand, ferroelectric polarization can efficiently and directionally regulate the movement of carriers, which provides the possibility to improve the synaptic properties of such materials. In this study, electronic synapses based on the SIO epitaxial film with introducing a ferroelectric PbZr0.2Ti0.8O3 (PZT) layer, multiple important synaptic plasticity functions including paired-pulse depression, spike-rate-dependent plasticity, spike-time-dependent plasticity, and abnormal Bienenstock–Cooper–Munro learning rule have been simulated by electrical stimulation. Furthermore, the PZT/SIO/Nb:SrTiO3 (NSTO) device exhibits larger synaptic weight and dynamic range of conductance and requires less training pulses compared to the SIO/NSTO device, which may be attributed to the enhanced modulation of the variation in the SIO/NSTO interface barrier by the polarization field. This research makes a great contribution to the efficient and fast information transmission of neuromorphic computing. [ABSTRACT FROM AUTHOR]

A ferroelectric memristor has attracted much attention due to convenient controlling by polarization switching, but the resistive switching has been attributed to the drift or charge trapping of defects. To distinguish the resistive switching mechanism between ferroelectric polarization switching and the normal resistive switching mechanism such as the drift or charge trapping of defects, BaTiO3 (BTO) thin films were grown on a (001) Nb:SrTiO3 single crystal substrate by pulsed laser deposition with high and low laser energy density. Based on a piezoelectric force microscope, ferroelectricity is found in BTO thin films grown at high laser energy density. X-ray photoelectron spectroscopy further confirms the existence of defects in the BTO films grown at low laser energy density. The high energy sample with low density of defects exhibits a resistance hysteresis loop but little current hysteresis loop, while the low energy sample with high density of defects shows a significant resistance and current hysteresis loop simultaneously. These results provide a deep understanding about the resistive switching from ferroelectric polarization switching and the drift or charge trapping of defects. [ABSTRACT FROM AUTHOR]

Introducing magnetic order into a topological insulator via the magnetic proximity effect can break the time-reversal symmetry of the topological surface states, resulting in a variety of exotic physical phenomena that are expected to be applied in spintronic devices. However, in the topological insulator/ferromagnet heterostructures obtained so far, the interfacial hybridization is too weak and difficult to induce sufficiently strong magnetism in the topological insulator. In this work, we investigate the electrical transport properties of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures and demonstrate the presence of the magnetic proximity effect in them. The Curie temperature of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures was found to be increased by about 25 K. The coercive field was suppressed in the magnetoresistance; the Hall curves of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures exhibited different orientations and appeared non-linear behavior at high fields, and the anisotropic magnetoresistance changed from twofold rotational symmetry to quadruple symmetry. These provide direct evidence for the emergence of the magnetic proximity effect. This work will help to study the magnetic proximity effect in the topological insulators and paves the way for spintronic devices in the future. [ABSTRACT FROM AUTHOR]

Anomalous Hall effect, an interesting transport behavior, is of importance topic for fundamental physics and device application. Recently, the sign change of anomalous Hall effect (AHE) in some materials has being concerned. Here, we study the electrical transport, magnetic properties, and AHE of Cr2.63V0.25Te4 single crystals. Cr2.63V0.25Te4 shows a bad metal behavior with a resistivity kink at 178 K, corresponding to a peak on a heat capacity–temperature curve, and the strong electron correlation should be a dominant transport mechanism below 178 K. At this temperature, the magnetization shows a sharp magnetic transition. The linear Hall resistivity at a high field with a positive slope suggests a p-type conductivity for bulk Cr2.63V0.25Te4. The clear AHE is observed below 180 K with a larger anomalous Hall conductivity σxy ∼ 2000 Ω−1 cm−1 at 3 K. For 3–60 K, an AHE coefficient Rs is negative, and Rs is positive between 100 and 180 K. The sign change of AHE may be due to Fermi level crossing the overlap of 3d band in ferromagnetic transition-metal materials. Based on our analysis, the AHE mechanism should be the skew scattering. Our results reveal the interesting physical properties in Cr2.63V0.25Te4 single crystals and give another system to study AHE for future Hall device design. [ABSTRACT FROM AUTHOR]

Ta2Pd3Te5 has been recently identified as a van der Waals topological crystalline insulator candidate, but its magnetotransport properties are not reported. Here, we study electrical transport properties of Ta2Pd3Te5 single crystals. Ta2Pd3Te5 shows an insulating behavior with a trend of saturation below 20 K. The activity energy determined from the fits to polaron hopping model is Ea ∼ 36.1 meV, close to the value of 42 meV determined from previous scanning tunneling microscopy measurement. The linear Hall resistivity with a negative slope suggests an n-type conductivity for bulk Ta2Pd3Te5. The magnetoresistance (MR) is positive at 2 K, and the dip-like feature at low magnetic fields is attributed to the weak antilocalization effect. On the other hand, a negative low-field MR develops in the temperature range between 5 and 30 K, which is identified as a fingerprint of the weak localization effect. Such a transition from weak antilocalization to weak localization with increasing temperature reveals that the spin–orbit interaction plays an important role in Ta2Pd3Te5. Our results reveal highly enriched physical properties in Ta2Pd3Te5 single crystals, and they can be exploited in future magnetoresistance device design. [ABSTRACT FROM AUTHOR]

Temperature- and pulse amplitude/width dependent current-voltage characteristics were performed to study the variance of negative differential resistance (NDR) features accompanying bipolar resistive switching. Interestingly, the absolute value of the NDR peak intensity is enhanced at first and then weakened, while the NDR peak position gradually shifts toward the lower absolute bias value with an increase in temperature from 140 to 300 K, and shifts toward the larger absolute bias value with an increase in temperature from 300 to 400 K. Furthermore, the NDR peak is absent after applying a small and narrow positive pulse, while it gradually increases with increasing the applied pulse amplitude or width. These temperature- and pulse-dependent NDR behaviors can be fully understood based on a model of generation and drift of ionized oxygen vacancies coupled with trapping/detrapping electrons. The clarification of the mechanism will pave the way for practical applications. [ABSTRACT FROM AUTHOR]

Defects play an important and in many cases dominant role in the physical and chemical properties of many oxide materials. In this work, we show that the surface Ti3+ defects in SrTiO3 (STO), characterized by electron paramagnetic resonance and X-ray photoelectron spectroscopy, directly impact the photocatalytic activity of STO. O2 species are found to absorb preferentially on Ti3+ defect sites. Hydrogen evolution under ambient air diminishes with the increase in the concentration of surface Ti3+ . This is explained by the over-accumulation of Pt cocatalysts on the site of surface Ti3+ defects after the removal of adsorbed O2. [ABSTRACT FROM AUTHOR]

Defects play an important and in many cases dominant role in the physical and chemical properties of many oxide materials. In this work, we show that the surface Ti3+ defects in SrTiO3 (STO), characterized by electron paramagnetic resonance and X-ray photoelectron spectroscopy, directly impact the photocatalytic activity of STO. O2 species are found to absorb preferentially on Ti3+ defect sites. Hydrogen evolution under ambient air diminishes with the increase in the concentration of surface Ti3+ . This is explained by the over-accumulation of Pt cocatalysts on the site of surface Ti3+ defects after the removal of adsorbed O2. [ABSTRACT FROM AUTHOR]

Introducing magnetic order into a topological insulator via the magnetic proximity effect can break the time-reversal symmetry of the topological surface states, resulting in a variety of exotic physical phenomena that are expected to be applied in spintronic devices. However, in the topological insulator/ferromagnet heterostructures obtained so far, the interfacial hybridization is too weak and difficult to induce sufficiently strong magnetism in the topological insulator. In this work, we investigate the electrical transport properties of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures and demonstrate the presence of the magnetic proximity effect in them. The Curie temperature of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures was found to be increased by about 25 K. The coercive field was suppressed in the magnetoresistance; the Hall curves of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures exhibited different orientations and appeared non-linear behavior at high fields, and the anisotropic magnetoresistance changed from twofold rotational symmetry to quadruple symmetry. These provide direct evidence for the emergence of the magnetic proximity effect. This work will help to study the magnetic proximity effect in the topological insulators and paves the way for spintronic devices in the future. [ABSTRACT FROM AUTHOR]

Ta2Pd3Te5 has been recently identified as a van der Waals topological crystalline insulator candidate, but its magnetotransport properties are not reported. Here, we study electrical transport properties of Ta2Pd3Te5 single crystals. Ta2Pd3Te5 shows an insulating behavior with a trend of saturation below 20 K. The activity energy determined from the fits to polaron hopping model is Ea ∼ 36.1 meV, close to the value of 42 meV determined from previous scanning tunneling microscopy measurement. The linear Hall resistivity with a negative slope suggests an n-type conductivity for bulk Ta2Pd3Te5. The magnetoresistance (MR) is positive at 2 K, and the dip-like feature at low magnetic fields is attributed to the weak antilocalization effect. On the other hand, a negative low-field MR develops in the temperature range between 5 and 30 K, which is identified as a fingerprint of the weak localization effect. Such a transition from weak antilocalization to weak localization with increasing temperature reveals that the spin–orbit interaction plays an important role in Ta2Pd3Te5. Our results reveal highly enriched physical properties in Ta2Pd3Te5 single crystals, and they can be exploited in future magnetoresistance device design. [ABSTRACT FROM AUTHOR]