Phonon-mediated spin transport in quantum paraelectric metals

Fuente: arXiv
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Main Authors: Kim, Kyoung-Min, Chung, Suk Bum
Format: Preprint
Published: 2024
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author Kim, Kyoung-Min
Chung, Suk Bum
author_facet Kim, Kyoung-Min
Chung, Suk Bum
contents The concept of ferroelectricity is now often extended to include continuous inversion symmetry-breaking transitions in various metals and doped semiconductors. Paraelectric metals near ferroelectric quantum criticality, which we term `quantum paraelectric metals,' typically possess soft transverse optical phonons that have Rashba-type coupling to itinerant electrons in the presence of spin-orbit coupling. We find through the Kubo formula calculation that such Rashba electron-phonon coupling has a profound impact on electron spin transport. While the spin Hall effect arising from non-trivial electronic band structures has been studied extensively, we find here the presence of the Rashba electron-phonon coupling can give rise to spin current, including spin Hall current, in response to an inhomogeneous electric field even with a completely trivial band structure. Furthermore, this spin conductivity displays unconventional characteristics, such as quadrupolar symmetry associated with the wave vector of the electric field and a thermal activation behavior characterized by scaling laws dependent on the phonon frequency to temperature ratio. These findings shed light on exotic electronic transport phenomena originating from ferroelectric quantum criticality, highlighting the intricate interplay of charge and spin degrees of freedom.
format Preprint
id arxiv_https___arxiv_org_abs_2401_11164
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Phonon-mediated spin transport in quantum paraelectric metals
Kim, Kyoung-Min
Chung, Suk Bum
Strongly Correlated Electrons
The concept of ferroelectricity is now often extended to include continuous inversion symmetry-breaking transitions in various metals and doped semiconductors. Paraelectric metals near ferroelectric quantum criticality, which we term `quantum paraelectric metals,' typically possess soft transverse optical phonons that have Rashba-type coupling to itinerant electrons in the presence of spin-orbit coupling. We find through the Kubo formula calculation that such Rashba electron-phonon coupling has a profound impact on electron spin transport. While the spin Hall effect arising from non-trivial electronic band structures has been studied extensively, we find here the presence of the Rashba electron-phonon coupling can give rise to spin current, including spin Hall current, in response to an inhomogeneous electric field even with a completely trivial band structure. Furthermore, this spin conductivity displays unconventional characteristics, such as quadrupolar symmetry associated with the wave vector of the electric field and a thermal activation behavior characterized by scaling laws dependent on the phonon frequency to temperature ratio. These findings shed light on exotic electronic transport phenomena originating from ferroelectric quantum criticality, highlighting the intricate interplay of charge and spin degrees of freedom.
title Phonon-mediated spin transport in quantum paraelectric metals
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2401.11164