Theory of quantum paraelectrics and the metaelectric transition

Conduit, Gareth; Simons, Benjamin D.

doi:10.1103/physrevb.81.024102

Cited by 21 publications

(10 citation statements)

References 28 publications

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“…x O 1−x ) 3 has been studied for varying x at very low temperatures at ambient pressure; because it does not depend strongly on sample growth conditions or purity, it has been suggested that disorder is not a key feature [22]. The detailed behavior of the dielectric response is in excellent agreement with theoretical predictions [9,17,18,19,20,22,59,60,77,82], suggesting that this is a system where detailed interaction between theory and experiment are possible. Work is currently in progress on the Grüneisen ratio [66] in this same set of materials to explore its behavior at and in proximity to the DFE-QCP (displacive ferroelectric quantum critical point) [67].…”

Section: The Case Of Srt Io 3 To Datementioning

confidence: 77%

“…It was assumed that the stability of the paraelectric state in low temperature STO is due to effects of zero-point fluctuations analogous to the situation in liquid helium where crystallization is never achieved at ambient pressure. There was already prior theoretical literature on the effects of quantum fluctuations on low temperature displacive transitions [16,17,59,60,62], and experiments on STO stimulated more theoretical research in this direction [9,18,19,20,22,80,81,82]. Usually one associates zero-point fluctuations with light atoms like hydrogen or helium so their significance for STO may seem surprising.…”

Section: The Case Of Srt Io 3 To Datementioning

confidence: 99%

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Prospects and applications near ferroelectric quantum phase transitions: a key issues review

et al. 2017

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The emergence of complex and fascinating states of quantum matter in the neighborhood of zero temperature phase transitions suggests that such quantum phenomena should be studied in a variety of settings. Advanced technologies of the future may be fabricated from materials where the cooperative behavior of charge, spin and current can be manipulated at cryogenic temperatures. The progagating lattice dynamics of displacive ferroelectrics make them appealing for the study of quantum critical phenomena that is characterized by both space- and time-dependent quantities. In this key issues article we aim to provide a self-contained overview of ferroelectrics near quantum phase transitions. Unlike most magnetic cases, the ferroelectric quantum critical point can be tuned experimentally to reside at, above or below its upper critical dimension; this feature allows for detailed interplay between experiment and theory using both scaling and self-consistent field models. Empirically the sensitivity of the ferroelectric T 's to external and to chemical pressure gives practical access to a broad range of temperature behavior over several hundreds of Kelvin. Additional degrees of freedom like charge and spin can be added and characterized systematically. Satellite memories, electrocaloric cooling and low-loss phased-array radar are among possible applications of low-temperature ferroelectrics. We end with open questions for future research that include textured polarization states and unusual forms of superconductivity that remain to be understood theoretically.

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Section: The Case Of Srt Io 3 To Datementioning

confidence: 77%

Section: The Case Of Srt Io 3 To Datementioning

confidence: 99%

Prospects and applications near ferroelectric quantum phase transitions: a key issues review

et al. 2017

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“…10 It has been suggested that EuTiO 3 is the prototype for studying quantum paraelectric behavior in magnetic systems. 11 In addition to these experiments on bulk EuTiO 3 , there has been a series of recent studies on EuTiO 3 thin films [12][13][14][15] motivated in part by the subsequently verified prediction that epitaxial strain should induce ferroelectricity and multiferroicity. 16,17 Likewise "chemical strain," i.e., doping at the A site with larger divalent ions, has been shown to induce ferroelectricity, e.g., in alloys with BaTiO 3 .…”

Section: Introductionmentioning

confidence: 99%

First-principles prediction of oxygen octahedral rotations in perovskite-structure EuTiO3

Rushchanskii¹,

Spaldin²,

Ležaić³

2012

Phys. Rev. B

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We present a systematic first-principles study of the structural and vibrational properties of perovskite-structure EuTiO 3 . Our calculated phonon spectrum of the high-symmetry cubic structural prototype shows strong M-and R-point instabilities, indicating a tendency to symmetry-lowering structural deformations composed of rotations and tilts of the oxygen octahedra. Subsequent explicit study of 14 different octahedral tilt-patterns showed that the I 4/mcm, I mma, and R3c structures, all with antiferrodistortive rotations of the octahedra, have significantly lower total energy than the prototype P m3m structure. We discuss the dynamical stability of these structures, and the influence of the antiferrodistortive structural distortions on the vibrational, optical, and magnetic properties of EuTiO 3 , in the context of recent unexplained experimental observations.

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“…The bosonic propagator describing the FE fluctuations in the disordered state is given by [12,30,31,37,38]…”

Section: A Bosonic Propagator: Optical Phononsmentioning

confidence: 99%

Anisotropic superconductivity mediated by ferroelectric fluctuations in cubic systems with spin-orbit coupling

Gastiasoro,

Trevisan,

Fernandes

2020

Preprint

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Motivated by the experimental observation that superconductivity in bulk doped SrTiO3 is enhanced as a putative ferroelectric quantum critical point (FE-QCP) is approached, we study the pairing instability of a cubic system in which electrons exchange low-energy ferroelectric fluctuations. Instead of the gradient coupling to the lattice distortion associated with ferroelectricity, we consider a direct coupling between the electrons and the bosonic ferroelectric field that appears in the presence of spin-orbit coupling. Working in the weak-coupling regime, we find that the pairing interaction is dominated by the soft transverse optical (TO) mode, resulting in a Tc enhancement upon approaching the FE-QCP. Focusing on even-parity states, we find that although the s-wave state always wins, states with higher Cooper-pair angular momentum become close competitors as the TO mode softens. We show that the cubic anisotropy of the FE fluctuations mixes the s-wave and g-wave states, resulting in a characteristic anisotropy of the gap function. The gap anisotropy behaves non-monotonically as the FE-QCP is approached: upon decreasing the TO mode frequency, the gap anisotropy first changes sign and then increases in magnitude. We discuss the possible applications of our results to the superconducting state of SrTiO3.

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Theory of quantum paraelectrics and the metaelectric transition

Cited by 21 publications

References 28 publications

Prospects and applications near ferroelectric quantum phase transitions: a key issues review

Prospects and applications near ferroelectric quantum phase transitions: a key issues review

First-principles prediction of oxygen octahedral rotations in perovskite-structure EuTiO3

Anisotropic superconductivity mediated by ferroelectric fluctuations in cubic systems with spin-orbit coupling

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