Raman Circular Dichroism and Quantum Geometry of Chiral Quantum Spin Liquids

Fuente: arXiv
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Main Authors: Koller, Eduard, Leeb, Valentin, Perkins, Natalia B., Knolle, Johannes
Format: Preprint
Published: 2025
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author Koller, Eduard
Leeb, Valentin
Perkins, Natalia B.
Knolle, Johannes
author_facet Koller, Eduard
Leeb, Valentin
Perkins, Natalia B.
Knolle, Johannes
contents We show that the quantum geometry of fractionalized spin excitations in Mott-insulating quantum spin liquids (QSL) gives rise to a finite Raman circular dichroism (RCD) signal. We demonstrate the equivalence between the Loudon-Fleury framework and the light-matter coupling approach for effective spinon bands. Using the latter, we derive an analytical decomposition of the RCD into different contributions of the quantum geometry. This reveals the sensitivity of the RCD to the underlying structure of the wave functions and the handedness of the excitations, rather than a nonzero Chern number of spinon excitations. To illustrate this, we apply our approach to two examples, the Kitaev honeycomb model in a magnetic field and a chiral $U(1)$ QSL on the triangular lattice, and discuss its experimental relevance for candidate materials.
format Preprint
id arxiv_https___arxiv_org_abs_2503_14091
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Raman Circular Dichroism and Quantum Geometry of Chiral Quantum Spin Liquids
Koller, Eduard
Leeb, Valentin
Perkins, Natalia B.
Knolle, Johannes
Strongly Correlated Electrons
We show that the quantum geometry of fractionalized spin excitations in Mott-insulating quantum spin liquids (QSL) gives rise to a finite Raman circular dichroism (RCD) signal. We demonstrate the equivalence between the Loudon-Fleury framework and the light-matter coupling approach for effective spinon bands. Using the latter, we derive an analytical decomposition of the RCD into different contributions of the quantum geometry. This reveals the sensitivity of the RCD to the underlying structure of the wave functions and the handedness of the excitations, rather than a nonzero Chern number of spinon excitations. To illustrate this, we apply our approach to two examples, the Kitaev honeycomb model in a magnetic field and a chiral $U(1)$ QSL on the triangular lattice, and discuss its experimental relevance for candidate materials.
title Raman Circular Dichroism and Quantum Geometry of Chiral Quantum Spin Liquids
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2503.14091