Anomalous Spin Response and Virtual-Carrier-Mediated Magnetism in a Topological Insulator

We present a comprehensive theoretical study of the static spin response in HgTe quantum wells, revealing distinctive behavior for the topologically nontrivial inverted structure. Most strikingly, the q=0 (long-wavelength) spin susceptibility of the undoped topological-insulator system is constant a...

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Autores principales:	T. Kernreiter, M. Governale, U. Zülicke, E. M. Hankiewicz
Formato:	article
Lenguaje:	EN
Publicado:	American Physical Society 2016
Materias:	Physics QC1-999
Acceso en línea:	https://doaj.org/article/a0d2ef8d7ddf4ce6bf42a474996209b0
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spelling	oai:doaj.org-article:a0d2ef8d7ddf4ce6bf42a474996209b02021-12-02T11:29:26ZAnomalous Spin Response and Virtual-Carrier-Mediated Magnetism in a Topological Insulator10.1103/PhysRevX.6.0210102160-3308https://doaj.org/article/a0d2ef8d7ddf4ce6bf42a474996209b02016-04-01T00:00:00Zhttp://doi.org/10.1103/PhysRevX.6.021010http://doi.org/10.1103/PhysRevX.6.021010https://doaj.org/toc/2160-3308We present a comprehensive theoretical study of the static spin response in HgTe quantum wells, revealing distinctive behavior for the topologically nontrivial inverted structure. Most strikingly, the q=0 (long-wavelength) spin susceptibility of the undoped topological-insulator system is constant and equal to the value found for the gapless Dirac-like structure, whereas the same quantity shows the typical decrease with increasing band gap in the normal-insulator regime. We discuss ramifications for the ordering of localized magnetic moments present in the quantum well, both in the insulating and electron-doped situations. The spin response of edge states is also considered, and we extract effective Landé g factors for the bulk and edge electrons. The variety of counterintuitive spin-response properties revealed in our study arises from the system’s versatility in accessing situations where the charge-carrier dynamics can be governed by ordinary Schrödinger-type physics; it mimics the behavior of chiral Dirac fermions or reflects the material’s symmetry-protected topological order.T. KernreiterM. GovernaleU. ZülickeE. M. HankiewiczAmerican Physical SocietyarticlePhysicsQC1-999ENPhysical Review X, Vol 6, Iss 2, p 021010 (2016)
institution	DOAJ
collection	DOAJ
language	EN
topic	Physics QC1-999
spellingShingle	Physics QC1-999 T. Kernreiter M. Governale U. Zülicke E. M. Hankiewicz Anomalous Spin Response and Virtual-Carrier-Mediated Magnetism in a Topological Insulator
description	We present a comprehensive theoretical study of the static spin response in HgTe quantum wells, revealing distinctive behavior for the topologically nontrivial inverted structure. Most strikingly, the q=0 (long-wavelength) spin susceptibility of the undoped topological-insulator system is constant and equal to the value found for the gapless Dirac-like structure, whereas the same quantity shows the typical decrease with increasing band gap in the normal-insulator regime. We discuss ramifications for the ordering of localized magnetic moments present in the quantum well, both in the insulating and electron-doped situations. The spin response of edge states is also considered, and we extract effective Landé g factors for the bulk and edge electrons. The variety of counterintuitive spin-response properties revealed in our study arises from the system’s versatility in accessing situations where the charge-carrier dynamics can be governed by ordinary Schrödinger-type physics; it mimics the behavior of chiral Dirac fermions or reflects the material’s symmetry-protected topological order.
format	article
author	T. Kernreiter M. Governale U. Zülicke E. M. Hankiewicz
author_facet	T. Kernreiter M. Governale U. Zülicke E. M. Hankiewicz
author_sort	T. Kernreiter
title	Anomalous Spin Response and Virtual-Carrier-Mediated Magnetism in a Topological Insulator
title_short	Anomalous Spin Response and Virtual-Carrier-Mediated Magnetism in a Topological Insulator
title_full	Anomalous Spin Response and Virtual-Carrier-Mediated Magnetism in a Topological Insulator
title_fullStr	Anomalous Spin Response and Virtual-Carrier-Mediated Magnetism in a Topological Insulator
title_full_unstemmed	Anomalous Spin Response and Virtual-Carrier-Mediated Magnetism in a Topological Insulator
title_sort	anomalous spin response and virtual-carrier-mediated magnetism in a topological insulator
publisher	American Physical Society
publishDate	2016
url	https://doaj.org/article/a0d2ef8d7ddf4ce6bf42a474996209b0
work_keys_str_mv	AT tkernreiter anomalousspinresponseandvirtualcarriermediatedmagnetisminatopologicalinsulator AT mgovernale anomalousspinresponseandvirtualcarriermediatedmagnetisminatopologicalinsulator AT uzulicke anomalousspinresponseandvirtualcarriermediatedmagnetisminatopologicalinsulator AT emhankiewicz anomalousspinresponseandvirtualcarriermediatedmagnetisminatopologicalinsulator
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Anomalous Spin Response and Virtual-Carrier-Mediated Magnetism in a Topological Insulator

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