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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 ...
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 ...
Lamellar fluctuations melt ferroelectricity
(2023)
We consider a standard Ginzburg-Landau model of a ferroelectric whose electrical polarization
is coupled to gradients of elastic strain [1–4]. At the harmonic level, such flexoelectric interaction
is known to hybridize ...
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 ...
Negative Thermal Expansion in Open Perovskites near the Precipice of Structural Stability
(2018)
Negative thermal expansion (NTE) describes the anomalous propensity of materials to shrink when heated. Since its discovery, the NTE effect has been found in a wide variety of materials with an array of magnetic, electronic ...
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 ...
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 ...
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∗ ...
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 ...
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 ...