The electronic structures, magnetic transition and Fermi surface instability of room-temperature altermagnet KV$_{2}$Se$_{2}$O

Fuente: arXiv
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Main Authors: Xu, Yuanji, Zhang, Huiyuan, Feng, Maoyuan, Tian, Fuyang
Format: Preprint
Published: 2025
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_version_ 1866909792372523008
author Xu, Yuanji
Zhang, Huiyuan
Feng, Maoyuan
Tian, Fuyang
author_facet Xu, Yuanji
Zhang, Huiyuan
Feng, Maoyuan
Tian, Fuyang
contents Altermagnetism has recently emerged as a distinct and fundamental class of magnetic order. Exploring its interplay with quantum phenomena such as unconventional superconductivity, density-wave instabilities, and many-body effects represents a compelling frontier. In this work, we theoretically confirm the presence of high-temperature metallic altermagnetism in KV$_2$Se$_2$O. We demonstrate that the anomalous metal-insulator-metal transition arises from a Lifshitz transition associated with Fermi surface reconstruction. The previously reported spin-density wave gap is found to lie below the Fermi level in our study and is now recognized to be attributed to the V-shaped density of states, originating from orbital-selective and sublattice-resolved half-metal-like behavior on a specific V atom. Furthermore, we identify the instability from the nesting of spin-momentum-locked two-dimensional Fermi surfaces, which induces the SDW state. These findings position KV$_2$Se$_2$O as a promising platform for investigating the interplay among altermagnetism, unconventional superconductivity, and density-wave order.
format Preprint
id arxiv_https___arxiv_org_abs_2506_20968
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The electronic structures, magnetic transition and Fermi surface instability of room-temperature altermagnet KV$_{2}$Se$_{2}$O
Xu, Yuanji
Zhang, Huiyuan
Feng, Maoyuan
Tian, Fuyang
Strongly Correlated Electrons
Altermagnetism has recently emerged as a distinct and fundamental class of magnetic order. Exploring its interplay with quantum phenomena such as unconventional superconductivity, density-wave instabilities, and many-body effects represents a compelling frontier. In this work, we theoretically confirm the presence of high-temperature metallic altermagnetism in KV$_2$Se$_2$O. We demonstrate that the anomalous metal-insulator-metal transition arises from a Lifshitz transition associated with Fermi surface reconstruction. The previously reported spin-density wave gap is found to lie below the Fermi level in our study and is now recognized to be attributed to the V-shaped density of states, originating from orbital-selective and sublattice-resolved half-metal-like behavior on a specific V atom. Furthermore, we identify the instability from the nesting of spin-momentum-locked two-dimensional Fermi surfaces, which induces the SDW state. These findings position KV$_2$Se$_2$O as a promising platform for investigating the interplay among altermagnetism, unconventional superconductivity, and density-wave order.
title The electronic structures, magnetic transition and Fermi surface instability of room-temperature altermagnet KV$_{2}$Se$_{2}$O
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2506.20968