Orbital Edelstein effect from the gradient of a scalar potential

TL;DR

This paper investigates the orbital Edelstein effect caused by an asymmetric scalar potential, deriving its characteristics without relying on spin-orbit coupling, and highlighting its potential dominance over spin-based effects in clean systems.

Contribution

It introduces a new mechanism for the orbital Edelstein effect driven by scalar potential gradients and provides both quantitative and qualitative analyses confirming its significance.

Findings

OEE scales as the cube of the momentum relaxation time.

In clean, large systems with weak SOC, OEE can surpass spin Edelstein effect.

The effect offers an alternative interpretation for some spin Hall effect experiments.

Abstract

We study the orbital Edelstein effect (OEE) that originates from a particular inversion symmetry breaking mechanism: an asymmetric scalar potential. We compute OEE of this kind with the help of the Kubo formula in the diffusive regime for a parabolic band Hamiltonian. We also present a qualitative derivation of the effect. Both approaches give the same result. This result does not rely on spin-orbit coupling (SOC) and scales as a cube of the momentum relaxation time. In sufficiently clean large systems with weak SOC, OEE of this nature should exceed the spin Edelstein effect by orders of magnitude. It may also provide an alternative interpretation for some experiments concerning the spin Hall effect.