Topological Nature of Orbital Chern Insulators

Fuente: arXiv
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Main Authors: Yao, Yueh-Ting, Chu, Chia-Hung, Bansil, Arun, Lin, Hsin, Chang, Tay-Rong
Format: Preprint
Published: 2025
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author Yao, Yueh-Ting
Chu, Chia-Hung
Bansil, Arun
Lin, Hsin
Chang, Tay-Rong
author_facet Yao, Yueh-Ting
Chu, Chia-Hung
Bansil, Arun
Lin, Hsin
Chang, Tay-Rong
contents Ground state topologies in quantum materials have unveiled many unique topological phases with novel Hall responses. Recently, the orbital Hall effect in insulators has suggested the existence of orbital Chern insulators (OCIs) in which the orbital angular momentum drives the Hall response. Studies on OCIs, however, have so far been restricted to valley-locked or spinful systems, but candidate materials for systematic studies of OCIs are lacking. Here we discuss a framework for investigating OCIs using the feature-spectrum topology approach. To characterize the ground-state topology in the orbital degree of freedom, we introduce the orbital Chern number and orbital-feature Berry curvature and demonstrate the bulk-boundary correspondence and orbital Hall response. We also uncover a parameter-driven topological phase transition, which would offer tunability of the OCIs. In this way, we identify monolayer blue-phosphorene (traditionally considered topologically trivial) as the primal 'hydrogen atom' of OCIs as a spinless, valley-free OCI material. Our study gives insight into the nature of orbital-driven topological phases and reveals a new facet of blue-phosphorene, and provides a new pathway for advancements in orbitronics and the discovery of novel topological materials.
format Preprint
id arxiv_https___arxiv_org_abs_2503_08138
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Topological Nature of Orbital Chern Insulators
Yao, Yueh-Ting
Chu, Chia-Hung
Bansil, Arun
Lin, Hsin
Chang, Tay-Rong
Materials Science
Ground state topologies in quantum materials have unveiled many unique topological phases with novel Hall responses. Recently, the orbital Hall effect in insulators has suggested the existence of orbital Chern insulators (OCIs) in which the orbital angular momentum drives the Hall response. Studies on OCIs, however, have so far been restricted to valley-locked or spinful systems, but candidate materials for systematic studies of OCIs are lacking. Here we discuss a framework for investigating OCIs using the feature-spectrum topology approach. To characterize the ground-state topology in the orbital degree of freedom, we introduce the orbital Chern number and orbital-feature Berry curvature and demonstrate the bulk-boundary correspondence and orbital Hall response. We also uncover a parameter-driven topological phase transition, which would offer tunability of the OCIs. In this way, we identify monolayer blue-phosphorene (traditionally considered topologically trivial) as the primal 'hydrogen atom' of OCIs as a spinless, valley-free OCI material. Our study gives insight into the nature of orbital-driven topological phases and reveals a new facet of blue-phosphorene, and provides a new pathway for advancements in orbitronics and the discovery of novel topological materials.
title Topological Nature of Orbital Chern Insulators
topic Materials Science
url https://arxiv.org/abs/2503.08138