Theory of local orbital magnetization: local Berry curvature

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Hauptverfasser: Saati, Sariah Al, Hur, Karyn Le, Piéchon, Frédéric
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Veröffentlicht: 2025
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author Saati, Sariah Al
Hur, Karyn Le
Piéchon, Frédéric
author_facet Saati, Sariah Al
Hur, Karyn Le
Piéchon, Frédéric
contents We present a microscopic theory for the local (single site) orbital magnetization in tight-binding systems. Each occupied state of energy $\varepsilon_n$ contributes with a local orbital magnetic moment term ${\mathbf{ m}}_n({\mathbf{ r}})$ and a local Berry-curvature term ${\mathbf{ Ω}}_n({\mathbf{ r}})$. For Bloch electrons (${\mathbf{ k}}$-space), we go beyond the modern theory by revealing the sublattice texture. We identify a topological contribution ${\mathbf{ Ω}}^{\text{topo}}_{n\mathbf{ k}}({\mathbf{ r}})$ and a geometric contribution ${\mathbfΩ}^{\text{geom}}_{n\mathbf{ k}}({\mathbf{ r}})$ to the sublattice Berry curvature. For systems with open boundaries (${\mathbf{ r}}$-space), we derive an explicit expression of an effective onsite Berry curvature ${\mathbf{ Ω}}_n({\mathbf{ r}})$. Considering two band models, the $\mathbf{ k}$-space and $\mathbf{ r}$-space onsite magnetizations coincide numerically but differ from the Bianco-Resta approach. They reveal orbital ferromagnetism in topological insulators, and orbital antiferro- and ferrimagnetism in trivial insulators. This theory can be used to investigate orbital magnetic textures and their topological properties in many systems of current interest (Moiré, amorphous, quasicrystals, defects, molecules).
format Preprint
id arxiv_https___arxiv_org_abs_2512_12343
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Theory of local orbital magnetization: local Berry curvature
Saati, Sariah Al
Hur, Karyn Le
Piéchon, Frédéric
Mesoscale and Nanoscale Physics
We present a microscopic theory for the local (single site) orbital magnetization in tight-binding systems. Each occupied state of energy $\varepsilon_n$ contributes with a local orbital magnetic moment term ${\mathbf{ m}}_n({\mathbf{ r}})$ and a local Berry-curvature term ${\mathbf{ Ω}}_n({\mathbf{ r}})$. For Bloch electrons (${\mathbf{ k}}$-space), we go beyond the modern theory by revealing the sublattice texture. We identify a topological contribution ${\mathbf{ Ω}}^{\text{topo}}_{n\mathbf{ k}}({\mathbf{ r}})$ and a geometric contribution ${\mathbfΩ}^{\text{geom}}_{n\mathbf{ k}}({\mathbf{ r}})$ to the sublattice Berry curvature. For systems with open boundaries (${\mathbf{ r}}$-space), we derive an explicit expression of an effective onsite Berry curvature ${\mathbf{ Ω}}_n({\mathbf{ r}})$. Considering two band models, the $\mathbf{ k}$-space and $\mathbf{ r}$-space onsite magnetizations coincide numerically but differ from the Bianco-Resta approach. They reveal orbital ferromagnetism in topological insulators, and orbital antiferro- and ferrimagnetism in trivial insulators. This theory can be used to investigate orbital magnetic textures and their topological properties in many systems of current interest (Moiré, amorphous, quasicrystals, defects, molecules).
title Theory of local orbital magnetization: local Berry curvature
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2512.12343