Fate of surface gaps in magnetic topological insulators

Fuente: arXiv
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Autores principales: Rostami, Habib, Moghaddam, Ali G.
Formato: Preprint
Publicado: 2024
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author Rostami, Habib
Moghaddam, Ali G.
author_facet Rostami, Habib
Moghaddam, Ali G.
contents In magnetic topological insulators, the surface states can exhibit a gap due to the breaking of time-reversal symmetry. Various experiments, while suggesting the existence of the surface gap, have raised questions about its underlying mechanism in the presence of different magnetic orderings. Here, we demonstrate that magnon-mediated electron-electron interactions, whose effects are not limited to the surfaces perpendicular to the magnetic ordering, can significantly influence surface states and their effective gaps. On the surfaces perpendicular to the spin quantization axis, many-body interactions can enhance the band gap to a degree that surpasses the non-interacting scenario. Then, on surfaces parallel to the magnetic ordering, we find that strong magnon-induced fermionic interactions can lead to features resembling a massless-like gap. These remarkable results largely stem from the fact that magnon-mediated interactions exhibit considerable long-range behavior compared to direct Coulomb interactions among electrons, thereby dominating the many-body properties at the surface of magnetic topological insulators.
format Preprint
id arxiv_https___arxiv_org_abs_2404_18917
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Fate of surface gaps in magnetic topological insulators
Rostami, Habib
Moghaddam, Ali G.
Mesoscale and Nanoscale Physics
In magnetic topological insulators, the surface states can exhibit a gap due to the breaking of time-reversal symmetry. Various experiments, while suggesting the existence of the surface gap, have raised questions about its underlying mechanism in the presence of different magnetic orderings. Here, we demonstrate that magnon-mediated electron-electron interactions, whose effects are not limited to the surfaces perpendicular to the magnetic ordering, can significantly influence surface states and their effective gaps. On the surfaces perpendicular to the spin quantization axis, many-body interactions can enhance the band gap to a degree that surpasses the non-interacting scenario. Then, on surfaces parallel to the magnetic ordering, we find that strong magnon-induced fermionic interactions can lead to features resembling a massless-like gap. These remarkable results largely stem from the fact that magnon-mediated interactions exhibit considerable long-range behavior compared to direct Coulomb interactions among electrons, thereby dominating the many-body properties at the surface of magnetic topological insulators.
title Fate of surface gaps in magnetic topological insulators
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2404.18917