Spontaneous spin-selective structural phase transition in chiral crystals

TL;DR

This paper predicts a unique chiral crystal phase transition driven by electron-phonon interactions, leading to spin-selective electronic gaps and helical spin density waves, with implications for chiral material design.

Contribution

It introduces a novel spin-selective phase transition in chiral crystals with screw symmetry, revealing new functional properties of chiral materials.

Findings

Phonon frequency depends on circular polarization handedness.

Soft phonon modes induce spin-selective Peierls gaps.

Chiral signatures influence collective mode behavior.

Abstract

In this Letter, we predict a structural phase transition unique to chiral crystals with screw symmetry. In chiral crystals, the phonon frequency renormalized by the electron-phonon coupling depends on the handedness of circular polarization. Consequently, the soft mode encoding phonon angular momentum induces spin-selective Peierls gaps in the electronic band, entailing a helical spin density wave and chiral lattice distortion. We also elucidate the chiral signatures and functional implications of collective modes. Our findings offer crucial insights into the emergence of chirality and highlight novel functional aspects of chiral materials and their design strategy.