Modeling chirality transfer at graphene–liquid crystal interfaces driven by non-collinear graphene corrugations

Abstract

Graphene exhibits optical chirality only when its in-plane mirror symmetries are broken—by strain corrugation, buckling, interlayer twist, chemical corrugation, or planar patterning—yet the microscopic route by which such interfacial handedness is transferred to adjacent otherwise achiral soft matter needs to be understood in full theoretical depth. We present a symmetry-based, predictive model showing that non-collinear corrugations of a graphene sheet generate a geometric pseudoscalar that acts as a chiral field at the graphene–liquid crystal (LC) interface. This field deracemizes configurationally achiral smectic-A LC molecules aligned by π–π stacking on the graphene surface and, under an out-of-plane electric field, drives a surface electroclinic effect (ECE)—a measure of chirality in the LC. The framework yields clear predictions: a single-pole frequency response; a rise-then-saturate behavior of the electroclinic coefficient with increasing graphene corrugation amplitude; and a monotonic increase of the cutoff frequency with roughness. The predictions are consistent with previously reported experimental observations, including graphene circular-dichroism studies and our companion LC measurements. The model explains why ultraflat graphene is optically achiral, yet strained graphene induces a robust interfacial ECE, and it provides practical design knobs for engineering chiral responses in 2D/soft-matter hybrids, opening a broadly applicable route to interfacial chirality control.