Antisymmetric linear transverse magnetization and ferroaxial moments induced by geometry-driven electric field gradients

TL;DR

This paper theoretically explores how electric field gradients from system geometry induce antisymmetric transverse magnetization and ferroaxial moments, revealing linear and quadratic dependencies useful for experiments.

Contribution

It demonstrates the generation and control of transverse magnetization and ferroaxial moments via geometry-driven electric field gradients, using the Kubo formalism and numerical simulations.

Findings

Transverse magnetization is antisymmetric and linear in magnetic field.

Total transverse magnetization scales linearly with electric field.

Longitudinal magnetization exhibits quadratic dependence on electric field.

Abstract

We theoretically investigate the transverse magnetization and ferroaxial moments induced by electric field gradients arising from the geometry of finite systems. Based on the Kubo formalism and real-time numerical simulations for a finite trapezoidal model, we demonstrate that both quantities are generated under the electric field gradient and are enhanced by tuning the leg inclination, which controls the gradient strength. We further show that the induced transverse magnetization is antisymmetric and linear in the magnetic field; such a response is prohibited by Onsager reciprocity in the absence of an electric field gradient. In addition, we find that the total transverse magnetization scales linearly with the electric field, in contrast to the longitudinal one, which exhibits a quadratic dependence, providing an advantage for experimental observation. Our results establish geometry-induced electric field gradients as a versatile mechanism for realizing and controlling unconventional transverse responses in mesoscopic systems.