Quantification of electronic asymmetry: chirality and axiality in solids

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 ${\Psi }^{†}{\gamma }^5\Psi$ 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.

9 pages, 7 figures

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Cited by in corpus (5)

• Purely Electronic Chirality without Structural Chirality
• Electron chirality and hydrodynamic helicity: Analysis in the atomic limit
• Theory of Many-Body Multipole Operators in Single-Centered Electron Systems: Two-Body Toroidal Monopoles in Spinless Orbitals
• Dirac bilinears in condensed matter physics: Relativistic correction for observables and conjugate electromagnetic fields
• Chirality-Induced Spin Currents in a Fermi Gas