Resolving spin currents and spin densities generated by charge-spin interconversion in systems with reduced crystal symmetry

TL;DR

This paper experimentally demonstrates that charge-to-spin interconversion in graphene-WTe2 systems with reduced symmetry induces spins in all three spatial directions, advancing control over spin generation in spintronics.

Contribution

It provides the first experimental evidence of anisotropic charge-to-spin interconversion with unconventional spin components in reduced symmetry systems.

Findings

CSI induces spins in all three spatial directions.

Disentangling CSI from spin Hall and inverse spin galvanic effects.

Experimental methodology for analyzing anisotropic spin generation.

Abstract

The ability to control the generation of spins in arbitrary directions is a long-sought goal in spintronics. Charge-to-spin interconversion (CSI) phenomena depend strongly on symmetry. Systems with reduced crystal symmetry allow anisotropic CSI with unconventional components, where charge and spin currents and the spin polarization are not mutually perpendicular to each other. Here, we demonstrate experimentally that the CSI in graphene-WTe2 induces spins with components in all three spatial directions. By performing multi-terminal nonlocal spin precession experiments, with specific magnetic field orientations, we discuss how to disentangle the CSI from the spin Hall and inverse spin galvanic effects.