A5070481715- Multiferroics and related materials
- Magnetic and transport properties of perovskites and related materials
- Ferroelectric and Piezoelectric Materials
- Advanced Condensed Matter Physics
- Advanced Thermoelectric Materials and Devices
- Thermal properties of materials
- Ferroelectric and Negative Capacitance Devices
- Semiconductor materials and devices
- Heusler alloys: electronic and magnetic properties
- Machine Learning in Materials Science
- Geophysical and Geoelectrical Methods
- Neural Networks and Applications
- Acoustic Wave Resonator Technologies
- Underwater Acoustics Research
- Advancements in Semiconductor Devices and Circuit Design
- Advanced Thermodynamics and Statistical Mechanics
- Dielectric materials and actuators
- Chemical and Physical Properties of Materials
- Microwave Dielectric Ceramics Synthesis
- Intermetallics and Advanced Alloy Properties
- Magnetic properties of thin films
- Solid-state spectroscopy and crystallography
- Rare-earth and actinide compounds
- Topological Materials and Phenomena
- Statistical Mechanics and Entropy
Luxembourg Institute of Science and Technology
2021-2024
Harvard University
2022
ETH Zurich
2015-2018
Ural Federal University
2013
Reducing the switching energy of ferroelectric thin films remains an important goal in pursuit ultralow-power memory and logic devices. Here, we elucidate fundamental role lattice dynamics by studying both freestanding bismuth ferrite (BiFeO
We use ab initio electronic structure calculations within the generalized gradient approximation (GGA+U) to density functional theory determine microscopic exchange interactions in series of orthorhombic rare-earth manganites, o-$R{\mathrm{MnO}}_{3}$. Our motivation is construct a model Hamiltonian (excluding effects due spin-orbit coupling), which can provide an accurate description magnetism these materials. First, we consider ${\mathrm{TbMnO}}_{3}$, exhibits spiral magnetic order at low...
The polarization response of antiferroelectrics to electric fields is such that the materials can store large energy densities, which makes them promising candidates for storage applications in pulsed-power technologies. However, relatively few this kind are known. Here, we consider ferroelectric/paraelectric superlattices as artificial electrostatically engineered antiferroelectrics. Specifically, using high-throughput second-principles calculations, engineer PbTiO 3 /SrTiO optimize their...
Abstract Understanding the electrical and thermal transport properties of materials is critical to design electronics, sensors, energy conversion devices. Computational modeling can accurately predict material but, in order be reliable, requires accurate descriptions electron phonon states their interactions. While first-principles methods are capable describing spectrum each carrier, using them compute still a formidable task, both computationally demanding memory intensive, requiring...
In this work we use a phenomenological theory of ferroelectric switching in <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:msub><a:mtext>BiFeO</a:mtext><a:mn>3</a:mn></a:msub></a:math> thin films to uncover the mechanism two-step process that leads reversal weak magnetization these materials. First, introduce realistic model <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:msub><b:mtext>BiFeO</b:mtext><b:mn>3</b:mn></b:msub></b:math> film, including Landau energy isolated...
Antiferroelectrics are valuable dielectric materials, offering promise for both high energy storage and solid-state caloric cooling applications. However, few antiferroelectrics known or available. Therefore, it is crucial to discover design materials showing antiferroelectric behaviour. In this study, we fabricated highly ordered lead scandium tantalate ceramics doped with calcium. From calorimetry polarization-electric field loops, demonstrate the effect of calcium on thermal properties...
Abstract The metastable nature of the ferroelectric phase HfO 2 is a significant impediment to its industrial application as functional material. In fact, no polar phases exist in bulk diagram , which shows dominant non-polar monoclinic ground state. As consequence, orthorhombic stabilized either kinetically or via epitaxial strain. Here, we propose an alternative approach, demonstrating feasibility thermodynamically stabilizing superlattices with other simple oxides. Using composition and...
Abstract The Seebeck coefficient and electrical conductivity are two central quantities to be optimized simultaneously in designing thermoelectric materials, they determined by the dynamics of carrier scattering. Here a new regime is uncovered where presence multiple electron bands with different effective masses, crossing near Fermi level, leads strong energy‐dependent lifetimes due intrinsic electron–phonon In this anomalous regime, decreases concentration, reverses sign even at high...
Orthorhombic rare-earth manganites, o-$R$MnO${}_{3}$ ($R$ is a cation or Y), are typical representatives of multiferroics in which ferroelectricity induced by magnetic order. They interest because their and ferroelectric properties can be strongly modified small external perturbations. Here, the authors use resonant nonresonant x-ray diffraction measurements, density functional theory, Monte Carlo simulations to investigate how manipulated using chemical pressure epitaxial strain. The...
In this work we introduce the simplest, lowest-order Landau-like potential for BiFeO$_3$ and La-doped as an expansion around paraelectric cubic phase in powers of polarization, FeO$_6$ octahedral rotations strains. We present analytical approach computing model parameters from density functional theory. illustrate our by potentials La$_{0.25}$Bi$_{0.75}$FeO$_3$ show that, overall, are able to capture first-principles results accurately. The computed models allow us identify explain main...
We use ab initio electronic structure calculations in combination with Monte Carlo simulations to investigate the magnetic and ferroelectric properties of bulk orthorhombic ${\mathrm{HoMnO}}_{3}$ ${\mathrm{ErMnO}}_{3}$. Our goals are explain inconsistencies measured perovskite manganites (o-$R{\mathrm{MnO}}_{3}$) small rare-earth ($R$) cations or Y, as well contradictions between directions amplitudes electric polarizations reported by different experimental groups. computations stabilize...
Abstract Reducing the switching energy of ferroelectric thin films remains an important goal in pursuit ultralow power memories and magnetoelectric spin-orbit logic devices. Here, we elucidate fundamental role lattice dynamics by combining thermodynamic calculations, experiments, phase-field simulations on both freestanding BiFeO 3 membranes clamped to a substrate. We observe distinct evolution domain pattern, from striped, 71° ferroelastic domains (spacing ~100 nm) films, large (10’s...
We present a short overview of different microscopic models for nonrelativistic and relativistic magnetoelectric coupling in 3d oxides with particular emphasis on multiferroic properties observed nonstoichiometric chain cuprates.
The metastable nature of the ferroelectric phase HfO$_2$ is a significant impediment to its industrial application as functional material. In fact, no polar phases exist in bulk diagram HfO$_2$, which shows dominant non-polar monoclinic ground state. As consequence, orthorhombic needs be kinetically stabilized. Here, we propose an alternative approach, demonstrating feasibility thermodynamically stabilizing superlattices with other simple oxides. Using composition and stacking direction...
Structural softness - often characterized by unstable phonon modes and large electromechanical responses is a hallmark of ferroelectric perovskites like BaTiO3 or Pb(Ti,Zr)O3. Whether HfO2 ferroelectrics present any such structural still matter debate. Here, using first principles calculations, we predict that it possible to induce instabilities in hafnia. More specifically, our calculations show in-plane epitaxial tensile strain causes mechanical instability the phase, which transforms...
The properties of functional oxide heterostructures are strongly influenced by the physics governing their interfaces. Modern deposition techniques allow us to accurately engineer interface through growth atomically precise heterostructures. This enables minute control over electronic, magnetic, and structural characteristics. Here, we investigate magnetic tailor-made superlattices employing ferromagnetic insulating double perovskites RE$_2$NiMnO$_6$ (RE = La, Nd), featuring distinct Curie...
In this work we use a phenomenological theory of ferroelectric switching in BiFeO$_3$ thin films to uncover the mechanism two-step process that leads reversal weak magnetization these materials. First, introduce realistic model film, including Landau energy isolated domains as well constraints account for presence substrate and multidomain configuration found experimentally. We obtain statistical information about behavior - by running dynamical simulations based on Landau-Khalatnikov...
In this work we introduce the simplest, lowest-order Landau-like potential for BiFeO$_3$ and La-doped as an expansion around paraelectric cubic phase in powers of polarization, FeO$_6$ octahedral rotations strains. We present analytical approach computing model parameters from density functional theory. illustrate our by potentials La$_{0.25}$Bi$_{0.75}$FeO$_3$ show that, overall, are able to capture first-principles results accurately. The computed models allow us identify explain main...