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Random Electric Field Instabilities of Relaxor Ferroelectrics
(2017-06-13)
Relaxor ferroelectrics are complex oxide materials which are rather unique to study the effects of compositional disorder on phase transitions. Here, we study the effects of quenched cubic random electric fields on the ...
Structure factor of a relaxor ferroelectric
(2015-04-14)
We study a minimal model for a relaxor ferroelectric including dipolar interactions, and short-range harmonic and anharmonic forces for the critical modes as in the theory of pure ferroelectrics together with quenched ...
Electronic structure of silicon-based nanostructures
(2007-08-30)
We have developed a unifying tight-binding Hamiltonian that can account for the electronic properties of recently proposed Si-based nanostructures, namely, Si graphene-like sheets and Si nanotubes. We considered the sp3s∗ ...
Why is the electrocaloric effect so small in ferroelectrics?
(2016-05-19)
Ferroelectrics are attractive candidate materials for environmentally friendly solid state refrigeration free of greenhouse gases. Their thermal response upon variations of external electric fields is largest in the vicinity ...
Large isotropic negative thermal expansion above a structural quantum phase transition
(2015-10-01)
Perovskite structured materials contain myriad tunable ordered phases of electronic and magnetic origin with proven technological importance and strong promise for a variety of energy solutions. An always-contributing ...
Cooperative elastic fluctuations provide tuning of the metal-insulator transition
(2019)
Metal-to-insulator transitions driven by strong electronic correlations occur frequently in condensed matter systems, and are associated with remarkable collective phenomena in solids, including superconductivity and ...
Pressure dependence of ferroelectric quantum critical fluctuation
(2019-12-13)
Phase transitions to a long-range-ordered state driven by a softened phonon mode are ubiquitous across condensed matter physics, but the evolution of such a mode as the system is tuned to or from the transition has never ...
Landau theory and giant room-temperature barocaloric effect
(2017-10-17)
The structural phase transitions of MF3 (M = Al, Cr, V, Fe, Ti, Sc) metal trifluorides are studied within a simple Landau theory consisting of tilts of rigid MF6 octahedra associated with soft antiferrodistortive optic ...
Fundamentals of silicene
(2017-08-02)
Silicene is a single atomic layer of silicon (Si) much like graphene, the first example of an elemental twodimensional (2D) nanomaterial whose study led to the 2010 Nobel Prize in Physics. Until 2010 or so, the only known ...
Quantum Ferroelectric Instabilities in Superconducting SrTiO3
(2018)
We examine the effects of strain and cation substitution on the superconducting phase of polar semiconductors near a ferroelectric quantum phase transition with a
model that combines a strong coupling theory of ...