Thermal Hall effects due to topological spin fluctuations in YMnO$_3$

Fuente: arXiv
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Main Authors: Kim, Ha-Leem, Saito, Takuma, Yang, Heejun, Ishizuka, Hiroaki, Coak, Matthew John, Lee, Jun Han, Sim, Hasung, Oh, Yoon Seok, Nagaosa, Naoto, Park, Je-Geun
Format: Preprint
Published: 2023
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author Kim, Ha-Leem
Saito, Takuma
Yang, Heejun
Ishizuka, Hiroaki
Coak, Matthew John
Lee, Jun Han
Sim, Hasung
Oh, Yoon Seok
Nagaosa, Naoto
Park, Je-Geun
author_facet Kim, Ha-Leem
Saito, Takuma
Yang, Heejun
Ishizuka, Hiroaki
Coak, Matthew John
Lee, Jun Han
Sim, Hasung
Oh, Yoon Seok
Nagaosa, Naoto
Park, Je-Geun
contents The thermal Hall effect in magnetic insulators has been considered a powerful method for examining the topological nature of charge-neutral quasiparticles such as magnons. Yet, unlike the kagome system, the triangular lattice has received less attention for studying the thermal Hall effect because the scalar spin chirality cancels out between adjacent triangles. However, such cancellation cannot be perfect if the triangular lattice is distorted, which could open the possibility of a non-zero thermal Hall effect. Here, we report that the trimerized triangular lattice of multiferroic hexagonal manganite YMnO$_3$ produces a highly unusual thermal Hall effect due to topological spin fluctuations with the additional intricacy of a Dzyaloshinskii-Moriya interaction under an applied magnetic field. We conclude the thermal Hall conductivity arises from the system's topological nature of spin fluctuations. Our theoretical calculations demonstrate that the thermal Hall conductivity is also related in this material to the splitting of the otherwise degenerate two chiralities, left and right, of its 120$^{\circ}$ magnetic structure. Our result is one of the most unusual cases of topological physics due to this broken $Z_2$ symmetry of the chirality in the supposedly paramagnetic state of YMnO$_3$, with strong topological spin fluctuations. These new mechanisms in this important class of materials are crucial in exploring new thermal Hall physics and exotic excitations.
format Preprint
id arxiv_https___arxiv_org_abs_2311_11527
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Thermal Hall effects due to topological spin fluctuations in YMnO$_3$
Kim, Ha-Leem
Saito, Takuma
Yang, Heejun
Ishizuka, Hiroaki
Coak, Matthew John
Lee, Jun Han
Sim, Hasung
Oh, Yoon Seok
Nagaosa, Naoto
Park, Je-Geun
Strongly Correlated Electrons
Materials Science
Other Condensed Matter
The thermal Hall effect in magnetic insulators has been considered a powerful method for examining the topological nature of charge-neutral quasiparticles such as magnons. Yet, unlike the kagome system, the triangular lattice has received less attention for studying the thermal Hall effect because the scalar spin chirality cancels out between adjacent triangles. However, such cancellation cannot be perfect if the triangular lattice is distorted, which could open the possibility of a non-zero thermal Hall effect. Here, we report that the trimerized triangular lattice of multiferroic hexagonal manganite YMnO$_3$ produces a highly unusual thermal Hall effect due to topological spin fluctuations with the additional intricacy of a Dzyaloshinskii-Moriya interaction under an applied magnetic field. We conclude the thermal Hall conductivity arises from the system's topological nature of spin fluctuations. Our theoretical calculations demonstrate that the thermal Hall conductivity is also related in this material to the splitting of the otherwise degenerate two chiralities, left and right, of its 120$^{\circ}$ magnetic structure. Our result is one of the most unusual cases of topological physics due to this broken $Z_2$ symmetry of the chirality in the supposedly paramagnetic state of YMnO$_3$, with strong topological spin fluctuations. These new mechanisms in this important class of materials are crucial in exploring new thermal Hall physics and exotic excitations.
title Thermal Hall effects due to topological spin fluctuations in YMnO$_3$
topic Strongly Correlated Electrons
Materials Science
Other Condensed Matter
url https://arxiv.org/abs/2311.11527