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arXiv · 2410.23549

Quantification of electronic asymmetry: chirality and axiality in solids

Tatsuya Miki·Hiroaki Ikeda·Michi-To Suzuki·Shintaro Hoshino
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Abstract

Chiral and axial materials offer platforms for intriguing phenomena, such as cross-correlated responses and chirality-induced spin selectivity. However, quantifying the properties of such materials has generally been considered challenging. Here, we demonstrate that the spatial distribution of the electron chirality, represented by $\Psi^\dagger \gamma^5 \Psi$ with the four-component Dirac field $\Psi$, characterizes the chirality and axiality of materials. Furthermore, we reveal that spin-derived electric polarization can serve as an effective indicator of material polarity. We present quantitative evaluations of electron chirality distribution and spin-derived electric polarization based on first-principles calculations. Additionally, we propose that electron chirality can be directly observed via circular dichroism in photoemission spectroscopy, which measures the difference between right- and left-handed circularly polarized light. Electron chirality and spin-derived electric polarization provide a new framework for quantifying chirality, axiality, and polarity in asymmetric materials, paving the way for the exploration of novel functional materials.

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Tatsuya Miki, Hiroaki Ikeda, Michi-To Suzuki, Shintaro Hoshino. 2024-10-31. Quantification of electronic asymmetry: chirality and axiality in solids. https://doi.org/10.1103/physrevlett.134.226401

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