Quantum geometric ferromagnetism by singular saddle point

Fuente: arXiv
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Hauptverfasser: Kitamura, Taisei, Nakai, Hiroki, Daido, Akito, Yanase, Youichi
Format: Preprint
Veröffentlicht: 2025
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author Kitamura, Taisei
Nakai, Hiroki
Daido, Akito
Yanase, Youichi
author_facet Kitamura, Taisei
Nakai, Hiroki
Daido, Akito
Yanase, Youichi
contents We propose ferromagnetism that occurs in electrons at a saddle point with band touching, which we call the singular saddle point. At the singular saddle point, the divergent quantum metric induces ferromagnetic correlation, and the logarithmic divergence of the density of states ensures ferromagnetism within Stoner theory. This is a prototypical example of quantum geometric ferromagnetism. The two-dimensional $t_{2g}$-orbital model accommodates the ferromagnetism by this mechanism, which is continuously connected to the exactly proven flat-band ferromagnetism.
format Preprint
id arxiv_https___arxiv_org_abs_2505_01089
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantum geometric ferromagnetism by singular saddle point
Kitamura, Taisei
Nakai, Hiroki
Daido, Akito
Yanase, Youichi
Strongly Correlated Electrons
We propose ferromagnetism that occurs in electrons at a saddle point with band touching, which we call the singular saddle point. At the singular saddle point, the divergent quantum metric induces ferromagnetic correlation, and the logarithmic divergence of the density of states ensures ferromagnetism within Stoner theory. This is a prototypical example of quantum geometric ferromagnetism. The two-dimensional $t_{2g}$-orbital model accommodates the ferromagnetism by this mechanism, which is continuously connected to the exactly proven flat-band ferromagnetism.
title Quantum geometric ferromagnetism by singular saddle point
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2505.01089