# Two-dimensional orbital Hall insulators

## TL;DR

This paper predicts a significant orbital Hall effect in two-dimensional multi-orbital materials, both metallic and insulating, with potential applications in spin-orbitronic devices due to large orbital currents.

## Contribution

It introduces the role of orbital textures in 2D materials and predicts large orbital Hall effects, expanding understanding beyond metallic systems.

## Key findings

- Large orbital Hall effect predicted in 2D materials
- Orbital Hall currents can surpass spin Hall currents
- Potential for novel spin-orbitronic device applications

## Abstract

The orbital-Hall effect (OHE), similarly to the spin-Hall effect (SHE), refers to the creation of a transverse flow of orbital angular momentum that is induced by a longitudinally applied electric field. For systems in which the spin-orbit coupling (SOC) is sizeable, the orbital and spin angular momentum degrees of freedom are coupled, and an interrelationship between charge, spin and orbital angular momentum excitations is naturally established. The OHE has been explored mostly in metallic systems, where it can be quite strong. However, several of its features remain unexplored in two-dimensional (2D) materials. Here, we investigate the role of orbital textures for the OHE displayed by multi-orbital 2D materials. We predict the appearance of a rather large orbital Hall effect in these systems both in their metallic and insulating phases. In some cases, the orbital Hall currents are larger than the spin Hall ones, and their use as information carriers widens the development possibilities of novel spin-orbitronic devices.