Giant Rashba spin splitting in strained KTaO3 ultrathin films for circular photogalvanic currents

Fuente: arXiv
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Auteurs principaux: Wu, Ning, Zhang, Xue-Jing, Liu, Bang-Gui
Format: Preprint
Publié: 2020
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author Wu, Ning
Zhang, Xue-Jing
Liu, Bang-Gui
author_facet Wu, Ning
Zhang, Xue-Jing
Liu, Bang-Gui
contents Strong Rashba effects at surfaces and interfaces have attracted great attention for basic scientific exploration and practical applications. Here, the first-principles investigation shows that giant and tunable Rashba effects can be achieved in KTaO$_3$ (KTO) ultrathin films by applying biaxial stress. When increasing the in-plane compressive strain nearly to -5\%, the Rashba spin splitting energy reaches $E_{R}=140$ meV, approximately corresponding to the Rashba coupling constant $α_{R}=1.3$ eV Å. We investigate its strain-dependent crystal structures, energy bands, and related properties, and thereby elucidate the mechanism for the giant Rashba effects. Furthermore, we show that giant Rashba spin splitting can be kept in the presence of SrTiO$_3$ capping layer and/or Si substrate, and strong circular photogalvanic effect can be achieved to generate spin-polarized currents in the KTO thin films or related heterostructures, which are promising for future spintronic and optoelectronic applications.
format Preprint
id arxiv_https___arxiv_org_abs_2001_04234
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Giant Rashba spin splitting in strained KTaO3 ultrathin films for circular photogalvanic currents
Wu, Ning
Zhang, Xue-Jing
Liu, Bang-Gui
Materials Science
Mesoscale and Nanoscale Physics
Strong Rashba effects at surfaces and interfaces have attracted great attention for basic scientific exploration and practical applications. Here, the first-principles investigation shows that giant and tunable Rashba effects can be achieved in KTaO$_3$ (KTO) ultrathin films by applying biaxial stress. When increasing the in-plane compressive strain nearly to -5\%, the Rashba spin splitting energy reaches $E_{R}=140$ meV, approximately corresponding to the Rashba coupling constant $α_{R}=1.3$ eV Å. We investigate its strain-dependent crystal structures, energy bands, and related properties, and thereby elucidate the mechanism for the giant Rashba effects. Furthermore, we show that giant Rashba spin splitting can be kept in the presence of SrTiO$_3$ capping layer and/or Si substrate, and strong circular photogalvanic effect can be achieved to generate spin-polarized currents in the KTO thin films or related heterostructures, which are promising for future spintronic and optoelectronic applications.
title Giant Rashba spin splitting in strained KTaO3 ultrathin films for circular photogalvanic currents
topic Materials Science
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2001.04234