The Piezochiral Effect

TL;DR

This paper introduces the piezochiral effect, a novel method to control chirality in crystals via mechanical strain, enabling continuous and reversible tuning of handedness with broad potential applications.

Contribution

The study reveals that uniaxial strain induces chirality in achiral crystals and experimentally demonstrates this in AgGaS2, providing a new approach for chirality control.

Findings

Uniaxial strain induces chirality in achiral crystals.

Strain-induced handedness can be tuned by strain direction or type.

Experimental verification in AgGaS2 confirms the effect.

Abstract

Chirality is a pervasive property of matter that underpins many important phenomena across physics, chemistry and biology. Given its broad significance, the development of protocols for rational control of chirality in solid state systems is highly desirable, especially if this effect can be tuned continuously and in two directions. Yet, this goal has remained elusive due to the absence of a universal conjugate field that couples linearly to this structural order. Here, we introduce the piezochiral effect, which enables control of chirality through mechanical strain. We first show by symmetry analysis that uniaxial strain induces chirality in a broad class of achiral crystals that host fragments of opposite chirality within each unit cell, an effect that has so far remained unrecognized. The strain-induced handedness can be tuned either by changing the strain direction or by switching between compressive and tensile strain. We experimentally verify this effect in AgGaS2, using measurements of the optical activity under strain. Our discovery establishes a new scheme for chirality control, with potential applications that range from spintronics to asymmetric catalysis, and enantioselective interactions in biosystems.