Creation and Manipulation of Higher-Order Topological States by Altermagnets

Fuente: arXiv
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Autores principales: Li, Yu-Xuan, Liu, Yichen, Liu, Cheng-Cheng
Formato: Preprint
Publicado: 2024
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author Li, Yu-Xuan
Liu, Yichen
Liu, Cheng-Cheng
author_facet Li, Yu-Xuan
Liu, Yichen
Liu, Cheng-Cheng
contents We propose to implement tunable higher-order topological states in a heterojunction consisting of a two-dimensional (2D) topological insulator and the recently discovered altermagnets, whose unique spin-polarization in both real and reciprocal space and null magnetization are in contrast to conventional ferromagnets and antiferromagnets. Based on symmetry analysis and effective edge theory, we show that the special spin splitting in altermagnets with different symmetries, such as $d$-wave, can introduce Dirac mass terms with opposite signs on the adjacent boundaries of the topological insulator, resulting in the higher-order topological state with mass-domain bound corner states. Moreover, by adjusting the direction of the Néel vector, we can manipulate such topological corner states by moving their positions. By first-principles calculations, taking a 2D topological insulator bismuthene with a square lattice on an altermagnet MnF$_2$ as an example, we demonstrate the feasibility of creating and manipulating the higher-order topological states through altermagnets. Finally, we discuss the experimental implementation and detection of the tunable topological corner states, as well as the potential non-Abelian braiding of the Dirac corner fermions.
format Preprint
id arxiv_https___arxiv_org_abs_2404_14645
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Creation and Manipulation of Higher-Order Topological States by Altermagnets
Li, Yu-Xuan
Liu, Yichen
Liu, Cheng-Cheng
Mesoscale and Nanoscale Physics
Materials Science
We propose to implement tunable higher-order topological states in a heterojunction consisting of a two-dimensional (2D) topological insulator and the recently discovered altermagnets, whose unique spin-polarization in both real and reciprocal space and null magnetization are in contrast to conventional ferromagnets and antiferromagnets. Based on symmetry analysis and effective edge theory, we show that the special spin splitting in altermagnets with different symmetries, such as $d$-wave, can introduce Dirac mass terms with opposite signs on the adjacent boundaries of the topological insulator, resulting in the higher-order topological state with mass-domain bound corner states. Moreover, by adjusting the direction of the Néel vector, we can manipulate such topological corner states by moving their positions. By first-principles calculations, taking a 2D topological insulator bismuthene with a square lattice on an altermagnet MnF$_2$ as an example, we demonstrate the feasibility of creating and manipulating the higher-order topological states through altermagnets. Finally, we discuss the experimental implementation and detection of the tunable topological corner states, as well as the potential non-Abelian braiding of the Dirac corner fermions.
title Creation and Manipulation of Higher-Order Topological States by Altermagnets
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2404.14645