Orbital Hall effect and orbital edge states caused by s electrons

TL;DR

This paper demonstrates that s-electron wave packets can generate orbital currents through cycloid trajectories, revealing a new mechanism for the orbital Hall effect in a minimal kagome lattice model.

Contribution

It introduces a novel mechanism for orbital current generation using s electrons and models it with a minimal kagome lattice system.

Findings

s-electron wave packets can transport orbital angular momentum

Cycloid trajectories induce orbital currents in surface states

Kagome lattice model captures the orbital Hall effect

Abstract

An orbital current can be generated whenever an object has a translational and rotational degree of freedom. In condensed matter physics, intra-atomic contributions to the transverse orbital transport, labeled orbital Hall effect, rely on propagating wave packets that must consist of hybridized atomic orbitals. However, inter-atomic contributions have to be considered as well because they give rise to a new mechanism for generating orbital currents. As we show, even wave packets consisting purely of s electrons can transport orbital angular momentum if they move on a cycloid trajectory. We introduce the kagome lattice with a single s orbital per atom as the minimal model for the orbital Hall effect and observe the cycloid motion of the electrons in the surface states.