Topological spiral magnetism in the Weyl semimetal SmAlSi

Fuente: arXiv
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Main Authors: Gaudet, Xiaohan Yao Jonathan, Verma, Rahul, Graf, David E., Yang, Hung-Yu, Bahrami, Faranak, Zhang, Ruiqi, Aczel, Adam A., Subedi, Sujan, Torchinsky, Darius H., Sun, Jianwei, Bansil, Arun, Huang, Shin-Ming, Singh, Bahadur, Nikolic, Predrag, Blaha, Peter, Tafti, Fazel
Format: Preprint
Published: 2022
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author Gaudet, Xiaohan Yao Jonathan
Verma, Rahul
Graf, David E.
Yang, Hung-Yu
Bahrami, Faranak
Zhang, Ruiqi
Aczel, Adam A.
Subedi, Sujan
Torchinsky, Darius H.
Sun, Jianwei
Bansil, Arun
Huang, Shin-Ming
Singh, Bahadur
Nikolic, Predrag
Blaha, Peter
Tafti, Fazel
author_facet Gaudet, Xiaohan Yao Jonathan
Verma, Rahul
Graf, David E.
Yang, Hung-Yu
Bahrami, Faranak
Zhang, Ruiqi
Aczel, Adam A.
Subedi, Sujan
Torchinsky, Darius H.
Sun, Jianwei
Bansil, Arun
Huang, Shin-Ming
Singh, Bahadur
Nikolic, Predrag
Blaha, Peter
Tafti, Fazel
contents Weyl electrons are intensely studied due to novel charge transport phenomena such as chiral anomaly, Fermi arcs, and photogalvanic effect. Recent theoretical works suggest that Weyl electrons can also participate in magnetic interactions, and the Weyl-mediated indirect exchange coupling between local moments is proposed as a new mechanism of spiral magnetism that involves chiral electrons. Despite reports of incommensurate and non-collinear magnetic ordering in Weyl semimetals, an actual spiral order has remained hitherto undetected. Here, we present evidence of Weyl-mediated spiral magnetism in SmAlSi from neutron diffraction, transport, and thermodynamic data. We show that the spiral order in SmAlSi results from the nesting between topologically non-trivial Fermi pockets and weak magnetocrystalline anisotropy, unlike related materials (Ce,Pr,Nd)AlSi, where a strong anisotropy prevents the spins from freely rotating. We map the magnetic phase diagram of SmAlSi and reveal an A-phase where topological magnetic excitations may exist. This is corroborated by the observation of a topological Hall effect within the A-phase.
format Preprint
id arxiv_https___arxiv_org_abs_2206_05121
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Topological spiral magnetism in the Weyl semimetal SmAlSi
Gaudet, Xiaohan Yao Jonathan
Verma, Rahul
Graf, David E.
Yang, Hung-Yu
Bahrami, Faranak
Zhang, Ruiqi
Aczel, Adam A.
Subedi, Sujan
Torchinsky, Darius H.
Sun, Jianwei
Bansil, Arun
Huang, Shin-Ming
Singh, Bahadur
Nikolic, Predrag
Blaha, Peter
Tafti, Fazel
Materials Science
Strongly Correlated Electrons
Weyl electrons are intensely studied due to novel charge transport phenomena such as chiral anomaly, Fermi arcs, and photogalvanic effect. Recent theoretical works suggest that Weyl electrons can also participate in magnetic interactions, and the Weyl-mediated indirect exchange coupling between local moments is proposed as a new mechanism of spiral magnetism that involves chiral electrons. Despite reports of incommensurate and non-collinear magnetic ordering in Weyl semimetals, an actual spiral order has remained hitherto undetected. Here, we present evidence of Weyl-mediated spiral magnetism in SmAlSi from neutron diffraction, transport, and thermodynamic data. We show that the spiral order in SmAlSi results from the nesting between topologically non-trivial Fermi pockets and weak magnetocrystalline anisotropy, unlike related materials (Ce,Pr,Nd)AlSi, where a strong anisotropy prevents the spins from freely rotating. We map the magnetic phase diagram of SmAlSi and reveal an A-phase where topological magnetic excitations may exist. This is corroborated by the observation of a topological Hall effect within the A-phase.
title Topological spiral magnetism in the Weyl semimetal SmAlSi
topic Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2206.05121