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The interfacial perpendicular magnetic anisotropy (PMA) observed at ferromagnet/oxide interfaces presents great promise for energy-efficient spintronic technologies. The epitaxial strain induced by the lattice mismatch between films and substrates serves as an effective strategy for the tuning of the material properties. However, the current understanding of the strain effects on interfacial PMA remains insufficient. Here, we present an extensive study of the biaxial strain effects on the interfacial magnetism and interfacial magnetic anisotropy constant ( K i ) in a slab-based Fe/MgO heterostructure using first-principles density functional theory calculations. Our results reveal a strong correlation between the spin moment of interfacial Fe atoms and the Fe-O bond length in both unstrained and strained systems. The overall K i , which includes contributions from both the Fe/MgO interface and the Fe surface, increases as the compressive strain increases. This is consistent with recent experimental findings that show that the PMA energy increases when the in-plane lattice constant of Fe decreases. In contrast, the overall K i initially decreases with a small tensile strain of less than 0.4% and shows an increasing trend as the tensile strain increases from 0.4% to 2%. However, beyond 2%, the overall K i decreases again. These changes in K i can be explained by the strain-induced variations of Fe 3d orbitals near the Fermi energy. This study provides a comprehensive understanding of the strain effects on magnetic anisotropy in Fe-based heterostructures, offering insights for the further optimization of interfacial magnetic properties. [ABSTRACT FROM AUTHOR]

We explored the possibility of producing a high-mobility two-dimensional electron gas (2DEG) in the LaAlO3/SrGeO3 and LaGaO3/BaSnO3 heterostructures using first-principles electronic structure calculations. Our results show that the 2DEG occurs at n-type LaAlO3/SrGeO3 and LaGaO3/BaSnO3 interfaces. Compared to the prototype LaAlO3/SrTiO3, LaAlO3/SrGeO3 and LaGaO3/BaSnO3 systems yield comparable total interfacial charge carrier density but much lower electron effective mass (nearly half the value of LaAlO3/SrTiO3), thus resulting in about twice larger electron mobility and enhanced interfacial conductivity. This work demonstrates that SrGeO3 and BaSnO3 can be potential substrate materials to achieve a high-mobility 2DEG in the perovskite-oxide heterostructures.

We explored the possibility of producing a high-mobility two-dimensional electron gas (2DEG) in the LaAlO3/SrGeO3 and LaGaO3/BaSnO3 heterostructures using first-principles electronic structure calculations. Our results show that the 2DEG occurs at n-type LaAlO3/SrGeO3 and LaGaO3/BaSnO3 interfaces. Compared to the prototype LaAlO3/SrTiO3, LaAlO3/SrGeO3 and LaGaO3/BaSnO3 systems yield comparable total interfacial charge carrier density but much lower electron effective mass (nearly half the value of LaAlO3/SrTiO3), thus resulting in about twice larger electron mobility and enhanced interfacial conductivity. This work demonstrates that SrGeO3 and BaSnO3 can be potential substrate materials to achieve a high-mobility 2DEG in the perovskite-oxide heterostructures.

The two-dimensional electron gas (2DEG) formed at the interface between two insulating oxides such as LaAlO3 and SrTiO3 (STO) is of fundamental and practical interest because of its novel interfacial conductivity and its promising applications in next-generation nanoelectronic devices. Here we show that a group of combinatorial descriptors that characterize the polar character, lattice mismatch, band gap, and the band alignment between the perovskite-oxide-based band insulators and the STO substrate, can be introduced to realize a high-throughput (HT) design of SrTiO3-based 2DEG systems from perovskite oxide quantum database. Equipped with these combinatorial descriptors, we have carried out a HT screening of all the polar perovskite compounds, uncovering 42 compounds of potential interests. Of these, Al-, Ga-, Sc-, and Ta-based compounds can form a 2DEG with STO, while In-based compounds exhibit a strain-induced strong polarization when deposited on STO substrate. In particular, the Ta-based compounds can form 2DEG with potentially high electron mobility at (TaO2)+/(SrO)0 interface. Our approach, by defining materials descriptors solely based on the bulk materials properties, and by relying on the perovskite-oriented quantum materials repository, opens new avenues for the discovery of perovskite-oxide-based functional interface materials in a HT fashion.

The primary objective of this investigation was to assess the viability of free and encapsulated Lactobacillus plantarum probiotics in mango juice and under simulated gastrointestinal conditions. Specifically, the probiotics were encapsulated using sodium alginate and alginate-soy protein isolate through the internal gelation method, and the obtained probiotics were characterized for various attributes. Both free and encapsulated probiotics were exposed to challenging conditions, including thermal stress, low temperature, and simulated gastrointestinal conditions. Additionally, both types of probiotics were incorporated into mango juice, and their survival was monitored over a 28-day storage period. Following viability under simulated gastrointestinal conditions, the count of free and encapsulated probiotic cells decreased from initial levels of 9.57 log CFU/mL, 9.55 log CFU/mL, and 9.53 log CFU/mL, 9.56 log CFU/mL to final levels of 6.14 log CFU/mL, 8.31 log CFU/mL, and 6.24 log CFU/mL, 8.62 log CFU/mL, respectively. Notably, encapsulated probiotics exhibited a decrease of 1.24 log CFU and 0.94 log CFU, while free cells experienced a reduction of 3.43 log CFU and 6.24 log CFU in mango juice over the storage period. Encapsulated probiotics demonstrated higher viability in mango juice compared to free probiotics throughout the 28-day storage period. These findings suggest that mango juice can be enriched with probiotics to create a health-promoting beverage. [ABSTRACT FROM AUTHOR]

We theoretically investigate the electronic and magnetic properties of the recently reported cubic and orthorhombically (Ortho.) distorted phases of PbMoO3, a 4d transition-metal perovskite oxide with almost half-filled t2g states. Our spin-polarized bare generalized gradient approximation results exhibit that the cubic phase is of low energy structure than the Ortho. one. However, on-site Coulomb repulsion in the range of 3.3 eV≤Ueff≤4.5 eV inclusion on Mo 4d orbitals reveals that at each value of Ueff, the Ortho. phase is more stable than the cubic one and with the increase in Ueff, both phases show more stability. We find a non-magnetic n-type conductivity with a high charge carrier density of ~1022cm-3 in both phases. Interestingly, a non-magnetic to magnetic phase transition occurs at Ueff=3.8 eV and 3.5 eV for the cubic and Ortho. phases, respectively. Moreover, a half-metallic ferromagnetic state is obtained at Ueff=4.1 eV and 4.3 eV for the cubic and Ortho. phases, respectively. Calculations also indicate a strong orbital hybridization between Pb 6p and Mo 4d, with a significant contribution of O 2p states. All findings are confirmed by the Yukawa screened Perdew-Burke-Ernzerhof 0 (YS-PBE0) hybrid functional. This work provokes further experimental investigations of magnetic properties of PbMoO3. [ABSTRACT FROM AUTHOR]

We studied the electronic properties and relative thermodynamic stability of several pentavalention (Ta, Nb, P, Sb, and I) doped SnO2 systems using first-principles hybrid density functional theory calculations, in order to evaluate their potential as transparent conducting oxides (TCOs). I-doped SnO2, though conductive, shows a narrowed optical band gap with respect to the undoped system due to the formation of gap states above the valence band. Nb-doped SnO2 forms localized impurity states below the conduction band bottom, suggesting that the Nb dopant exists as an Nb4+-like cation, which is consistent with the recent experimental finding of the formation of the impurity level below the conduction band bottom [Appl. Phys. Express 5, 061201 (2012)]. Ta- and Sb-doped SnO2 display n-type conductivity, high charge carrier density, and widened optical band gap. P-doped SnO2 shows similar n-type electronic properties with that of Sb- and Ta-doped systems, and thus P-doped SnO2 is proposed as a promising candidate TCofor further experimental validation. [ABSTRACT FROM AUTHOR]

We explore the possibility of achieving highly confined two-dimensional electron gas (2DEG) within one single atomic layer through a comprehensive comparison study on three prototypical perovskite heterostructures, LaAlO3/ATiO3 (A = Ca, Sr, and Ba), using first-principles electronic structure calculations. We predict that the heterostructure LaAlO3/BaTiO3 has a highly confined 2DEG within a single atomic layer of the substrate BaTiO3, and exhibits relatively higher interfacial charge carrier density and larger magnetic moments than the well-known LaAlO3/SrTiO3 system. The long Ti-O bond length in the ab-plane of the LaAlO3/BaTiO3 heterostructure is responsible for the superior charge confinement. We propose BaTiO3 as an exceptional substrate material for 2DEG systems with potentially superior properties. [ABSTRACT FROM AUTHOR]

Half-metallic ferromagnetic/ferrimagnetic (FiM) materials are a matter of enormous interest due to their potential technological applications in solid-state electronic devices. In this way, strain plays an important role to tune or control the physical properties of the systems; therefore, the influence of both biaxial ([110]) and hydrostatic ([111]) strain on the electronic and magnetic properties of recently synthesized double perovskite oxide Lu2NiIrO6 is investigated using density-functional theory calculations. The unstrained system exhibits a FiM Mott-insulating (i.e., having an energy gap of 0.20 eV) ground state due to strong antiferromagnetic superexchange coupling between high-energy half-filled Ni2+–e 2g ↑ and low-energy partially filled Ir4+ t 32g ↑t 22g ↓ orbitals. Interestingly, a half-metallic FiM state is predicted under biaxial and hydrostatic compressive strains of −8% and −6%, respectively. The admixture of Ir 5d orbitals in the spin-majority channel is mainly responsible for the conductivity with small contributions from Ni 3d orbitals. In contrast, all the tensile strain systems show almost the same electronic behavior (Mott-insulating FiM states) as found in the case of the unstrained system. The magnetic moments of the Ni (Ir) ion slightly decrease and increase as a function of compressive and tensile strains due to shortening and lengthening of the Ni–O(Ir–O) bond lengths, respectively. Moreover, our calculations show that compressive strain enhances the structural distortions, which could help to increase the Curie temperature of the system. [ABSTRACT FROM AUTHOR]

We explored the possibility of producing a high-mobility two-dimensional electron gas (2DEG) in the LaAlO3/SrGeO3 and LaGaO3/BaSnO3 heterostructures using first-principles electronic structure calculations. Our results show that the 2DEG occurs at n-type LaAlO3/SrGeO3 and LaGaO3/BaSnO3 interfaces. Compared to the prototype LaAlO3/SrTiO3, LaAlO3/SrGeO3 and LaGaO3/BaSnO3 systems yield comparable total interfacial charge carrier density but much lower electron effective mass (nearly half the value of LaAlO3/SrTiO3), thus resulting in about twice larger electron mobility and enhanced interfacial conductivity. This work demonstrates that SrGeO3 and BaSnO3 can be potential substrate materials to achieve a high-mobility 2DEG in the perovskite-oxide heterostructures. [ABSTRACT FROM AUTHOR]

Ab initio density functional theory calculations are employed for exploring the thermodynamic stability, vacancy defect formation energy and electronic structure of pristine and non-stoichiometric BaZrO3. The electronic properties of BaZrO3 show the hole-doped and insulating nature of cation and oxygen vacancies, respectively. The changes in the electronic properties of intrinsic vacancy containing BaZrO3 are analyzed in terms of electronic band structure, charge density and effective Bader charges. The relative stability of the formation of charge neutral and fully charged intrinsic vacancy defects in BaZrO3 is investigated in different chemical growth environments and the full and partial Schottky reactions are computed. Calculations are also performed to study the effects of oxygen vacancy clustering in different crystallographic planes. These calculations enable us to predict n-type conductivity in non-stoichiometric BaZrO3, which is useful for tailoring the electrical conduction of this material. Our results suggest that the semiconducting, p- and n-type character of BaZrO3 can be realized to enhance its device application by means of intentional incorporation of vacancy defects. [ABSTRACT FROM AUTHOR]

We studied the influence of uniaxial [100] strain (−1% to +1%) on the electron transport properties of a two-dimensional electron gas (2DEG) at the n-type interface of the LaAlO3/SrTiO3(LAO/STO) heterostructure (HS)-based slab system from the perspective of polarization effects via first-principles density functional theory calculations. We first analyzed the unstrained system, and found that the induced polarization toward the vacuum in the LAO film leads to a small charge carrier density on the order of 1013 cm−2 (less than the theoretical value of 3.3 × 1014 cm−2 from the superlattice-model-based polar catastrophe mechanism), which is in excellent agreement with the experimental values of oxygen-annealed LAO/STO HS samples. Upon applying [100] tensile strain on the STO substrate, we found a significant reduction of the induced polarization in the LAO film. This reduction weakens the driving force against charge transfer from LAO to STO, causing an increase in the interfacial charge carrier density. The uniaxial strain also leads to a decrease of the effective mass of interfacial mobile electrons, resulting in a higher electron mobility. These findings suggest that applying uniaxial [100] tensile strain on the STO substrate can significantly enhance the interfacial conductivity of the LAO/STO HS system, which gives a comprehensive explanation for experimental observations. In contrast, compressively strained LAO/STO systems show stronger LAO film polarization than the unstrained system, which reduces the interfacial charge carrier density and increases the electron effective mass, thus suppressing the interfacial conductivity. [ABSTRACT FROM AUTHOR]

The two-dimensional electron gas (2DEG) formed at the n-type (LaO)+1/(TiO2)0 interface in the polar/nonpolar LaAlO3/SrTiO3 (LAO/STO) heterostructure (HS) has emerged as a prominent research area because of its great potential for nanoelectronic applications. Due to its practical implementation in devices, desired physical properties such as high charge carrier density and mobility are vital. In this respect, 4d and 5d transition metal doping near the interfacial region is expected to tailor electronic properties of the LAO/STO HS system effectively. Herein, we studied Nb and Ta-doping effects on the energetics, electronic structure, interfacial charge carrier density, magnetic moment, and the charge confinements of the 2DEG at the n-type (LaO)+1/(TiO2)0 interface of LAO/STO HS using first-principles density functional theory calculations. We found that the substitutional doping of Nb(Ta) at Ti [Nb(Ta)@Ti] and Al [Nb(Ta)@Al] sites is energetically more favorable than that at La [Nb(Ta)@La] and Sr [Nb(Ta)@Sr] sites, and under appropriate thermodynamic conditions, the changes in the interfacial energy of HS systems upon Nb(Ta)@Ti and Nb(Ta)@Al doping are negative, implying that the formation of these structures is energetically favored. Our calculations also showed that Nb(Ta)@Ti and Nb(Ta)@Al doping significantly improve the interfacial charge carrier density with respect to that of the undoped system, which is because the Nb(Ta) dopant introduces excess free electrons into the system, and these free electrons reside mainly on the Nb(Ta) ions and interfacial Ti ions. Hence, along with the Ti 3d orbitals, the Nb 4d and Ta 5d orbitals also contribute to the interfacial metallic states; accordingly, the magnetic moments on the interfacial Ti ions increase significantly. As expected, the Nb@Al and Ta@Al doped LAO/STO HS systems show higher interfacial charge carrier density than the undoped and other doped systems. In contrast, Nb@Ti and Ta@Ti doped systems may show higher charge carrier mobility because of the lower electron effective mass. [ABSTRACT FROM AUTHOR]