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Phonon drag thermal Hall effect in metallic strontium titanate

SrTiO(3), a quantum paralectric, displays a detectable phonon thermal Hall effect (THE). Here, we show that the amplitude of the THE is extremely sensitive to stoichiometry. It drastically decreases upon substitution of a tiny fraction of Sr atoms with Ca, which stabilizes the ferroelectric order. I...

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Autores principales: Jiang, Shan, Li, Xiaokang, Fauqué, Benoît, Behnia, Kamran
Formato: Online Artículo Texto
Lenguaje:English
Publicado: National Academy of Sciences 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9436374/
https://www.ncbi.nlm.nih.gov/pubmed/35994652
http://dx.doi.org/10.1073/pnas.2201975119
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author Jiang, Shan
Li, Xiaokang
Fauqué, Benoît
Behnia, Kamran
author_facet Jiang, Shan
Li, Xiaokang
Fauqué, Benoît
Behnia, Kamran
author_sort Jiang, Shan
collection PubMed
description SrTiO(3), a quantum paralectric, displays a detectable phonon thermal Hall effect (THE). Here, we show that the amplitude of the THE is extremely sensitive to stoichiometry. It drastically decreases upon substitution of a tiny fraction of Sr atoms with Ca, which stabilizes the ferroelectric order. It drastically increases by an even lower density of oxygen vacancies, which turn the system to a dilute metal. The enhancement in the metallic state exceeds by far the sum of the electronic and the phononic contributions. We explain this observation as an outcome of three features: 1) Heat is mostly transported by phonons; 2) the electronic Hall angle is extremely large; and 3) there is substantial momentum exchange between electrons and phonons. Starting from Herring’s picture of phonon drag, we arrive to a quantitative account of the enhanced THE. Thus, phonon drag, hitherto detected as an amplifier of thermoelectric coefficients, can generate a purely thermal transverse response in a dilute metal with a large Hall angle. Our results reveal a hitherto-unknown consequence of momentum-conserving collisions between electrons and phonons.
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spelling pubmed-94363742023-02-22 Phonon drag thermal Hall effect in metallic strontium titanate Jiang, Shan Li, Xiaokang Fauqué, Benoît Behnia, Kamran Proc Natl Acad Sci U S A Physical Sciences SrTiO(3), a quantum paralectric, displays a detectable phonon thermal Hall effect (THE). Here, we show that the amplitude of the THE is extremely sensitive to stoichiometry. It drastically decreases upon substitution of a tiny fraction of Sr atoms with Ca, which stabilizes the ferroelectric order. It drastically increases by an even lower density of oxygen vacancies, which turn the system to a dilute metal. The enhancement in the metallic state exceeds by far the sum of the electronic and the phononic contributions. We explain this observation as an outcome of three features: 1) Heat is mostly transported by phonons; 2) the electronic Hall angle is extremely large; and 3) there is substantial momentum exchange between electrons and phonons. Starting from Herring’s picture of phonon drag, we arrive to a quantitative account of the enhanced THE. Thus, phonon drag, hitherto detected as an amplifier of thermoelectric coefficients, can generate a purely thermal transverse response in a dilute metal with a large Hall angle. Our results reveal a hitherto-unknown consequence of momentum-conserving collisions between electrons and phonons. National Academy of Sciences 2022-08-22 2022-08-30 /pmc/articles/PMC9436374/ /pubmed/35994652 http://dx.doi.org/10.1073/pnas.2201975119 Text en Copyright © 2022 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/This article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) .
spellingShingle Physical Sciences
Jiang, Shan
Li, Xiaokang
Fauqué, Benoît
Behnia, Kamran
Phonon drag thermal Hall effect in metallic strontium titanate
title Phonon drag thermal Hall effect in metallic strontium titanate
title_full Phonon drag thermal Hall effect in metallic strontium titanate
title_fullStr Phonon drag thermal Hall effect in metallic strontium titanate
title_full_unstemmed Phonon drag thermal Hall effect in metallic strontium titanate
title_short Phonon drag thermal Hall effect in metallic strontium titanate
title_sort phonon drag thermal hall effect in metallic strontium titanate
topic Physical Sciences
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9436374/
https://www.ncbi.nlm.nih.gov/pubmed/35994652
http://dx.doi.org/10.1073/pnas.2201975119
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