A5082069824- Multiferroics and related materials
- Ferroelectric and Piezoelectric Materials
- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Electronic and Structural Properties of Oxides
- Physics of Superconductivity and Magnetism
- Acoustic Wave Resonator Technologies
- Perovskite Materials and Applications
- Solid-state spectroscopy and crystallography
- 2D Materials and Applications
- Microwave Dielectric Ceramics Synthesis
- Advanced Battery Technologies Research
- Crystal Structures and Properties
- Magnetic properties of thin films
- Machine Learning in Materials Science
- Catalysis and Oxidation Reactions
- Photorefractive and Nonlinear Optics
- Magnetic Properties and Applications
- Sensor Technology and Measurement Systems
- Thermal Expansion and Ionic Conductivity
- Inorganic Fluorides and Related Compounds
- Inorganic Chemistry and Materials
- Surface and Thin Film Phenomena
- High-pressure geophysics and materials
- Topological Materials and Phenomena
Cornell University
2014-2024
Johns Hopkins University
2015
Drexel University
2012
University of California, Santa Barbara
2010
Argonne National Laboratory
2007-2008
Center for Nanoscale Materials
2007
Rutgers, The State University of New Jersey
1999-2006
Nano-C (United States)
2002
Villanova University
2002
First-principles calculations are presented for the layered perovskite Ca3Mn2O7. The results reveal a rich set of coupled structural, magnetic, and polar domains in which oxygen octahedron rotations induce ferroelectricity, magnetoelectricity, weak ferromagnetism. key point is that rotation distortion combination two nonpolar modes with different symmetries. We use term "hybrid" improper ferroelectricity to describe this phenomenon discuss how control over magnetism achieved through these...
We report the connection between stacking order and magnetic properties of bilayer CrI$_3$ using first-principles calculations. show that defines ground state. By changing interlayer one can tune exchange interaction antiferromagnetic ferromagnetic. To measure predicted stacking-dependent magnetism, we propose linear magnetoelectric effect. Our results not only gives a possible explanation for observed antiferromagnetism in but also have direct implications heterostructures made...
We use a combination of symmetry arguments and first-principles calculations to explore the connection between structural distortions ferroelectricity in perovskite family materials. explain role octahedral rotations suppressing these materials show that, as tolerance factor decreases, alone cannot fully suppress ferroelectricity. Our results that it is cation displacements ("hidden" Glazer notation) accompany rotations, rather than themselves, play decisive cases. knowledge gained our...
We have studied the structural phase transition of multiferroic $\mathrm{Y}\mathrm{Mn}{\mathrm{O}}_{3}$ from first principles. Using group-theoretical analysis and first-principles density functional calculations total energy phonons, we perform a systematic study surface around prototypic phase. find single instability at zone boundary which couples strongly to polarization. This coupling is mechanism that allows multiferroicity in this class materials. Our results imply an improper...
We propose a design strategy--based on the coupling of spins, optical phonons, and strain--for systems in which magnetic (electric) phase control can be achieved by an applied electric (magnetic) field. Using first-principles density-functional theory calculations, we present realization this strategy for perovskite EuTiO(3).
Increasing demands for electric field-tunable electric, magnetic, and orbital (EMO) materials has renewed interests in ferroelectricity its coupling to EMO properties complex perovskite oxides. The historic design strategy achieve a spontaneous polarization involves the incorporation of second-order Jahn-Teller (SOJT) active cations. challenge, however, is that this mechanism limited specific chemistries polar distortions arise are largely decoupled from properties, limiting their use as...
Abstract Ferroic transition metal oxides, which exhibit spontaneous elastic, electrical, magnetic, or toroidal order, functional properties that find use in ultrastable solid‐state memories, sensors, and medical imaging technologies. To realize multifunctional behavior, where one order parameter can be coupled to the conjugate field of another parameter, however, requires a common microscopic origin for long‐range order. Here, complete theory is formulated novel form ferroelectricity,...
We employ reactive molecular-beam epitaxy to synthesize the metastable perovskite SrIrO(3) and utilize in situ angle-resolved photoemission reveal its electronic structure as an exotic narrow-band semimetal. discover remarkably narrow bands which originate from a confluence of strong spin-orbit interactions, dimensionality, both in- out-of-plane IrO(6) octahedral rotations. The partial occupation numerous with strongly mixed orbital characters signals breakdown single-band Mott picture that...
We report on the discovery of a lead-free morphotropic phase boundary (MPB) in Sm doped BiFeO3 with simple perovskite structure using combinatorial thin film strategy. The is rhombohedral to pseudo-orthorhombic structural transition which exhibits ferroelectric antiferroelectric at approximately Bi0.86Sm0.14FeO3 dielectric constant and out-of-plane piezoelectric coefficient comparable those epitaxial (001) oriented PbZr0.52Ti0.48O3 (PZT) films MPB. discovered composition may be strong...
We present a strategy to design structures for which polar lattice distortion induces weak ferromagnetism. identify large class of multiferroic oxides as potential realizations and use density-functional theory screen several promising candidates. By elucidating the interplay between polarization Dzyaloshinskii-Moriya vector, we show how direction magnetization can be switched 180$^{\circ}$ symmetry equivalent states with an applied electric field.
We report the magnetic and electrical characteristics of polycrystalline FeTiO_{3} synthesized at high pressure that is isostructural with acentric LiNbO_{3} (LBO). Piezoresponse force microscopy, optical second harmonic generation, magnetometry demonstrate ferroelectricity below room temperature weak ferromagnetism approximately 120 K. These results validate symmetry-based criteria first-principles calculations coexistence in a series transition metal titanates crystallizing LBO structure.
The effects of ferroic distortion and biaxial strain on the band gap edges SrTiO$_{3}$ (STO) are calculated using density functional theory many-body perturbation theory. Anisotropic strains shown to reduce by breaking degeneracies at edges. Ferroic distortions widen allowing new edge orbital mixings. Compressive raise energies, while tensile lower them. To STO gap, one must symmetry from cubic suppressing distortions. Our calculations indicate that for engineered orientation growth...
Here we demonstrate how the Fermi surface topology and quantum many-body interactions can be manipulated via epitaxial strain in spin-triplet superconductor ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ its isoelectronic counterpart ${\mathrm{Ba}}_{2}{\mathrm{RuO}}_{4}$ using oxide molecular beam epitaxy, situ angle-resolved photoemission spectroscopy, transport measurements. Near topological transition of $\ensuremath{\gamma}$ sheet, observe clear signatures critical fluctuations, while...
Superconductivity is among the most fascinating and well-studied quantum states of matter. Despite over 100 years research, a detailed understanding how features normal-state electronic structure determine superconducting properties has remained elusive. For instance, ability to deterministically enhance transition temperature by design, rather than serendipity, been long sought-after goal in condensed matter physics materials science, but achieving this objective may require new tools,...