Spin polarisation and spin dependent scattering of holes in transverse magnetic focussing

TL;DR

This paper investigates how spin-dependent scattering affects magnetic focusing of holes in 2D systems with spin-orbit interaction, revealing that peak suppression is due to scattering changes, not spin polarisation variations.

Contribution

It demonstrates that in hole systems with $k^3$ spin-orbit interaction, peak suppression arises from scattering effects rather than spin polarisation, challenging previous assumptions.

Findings

Peak suppression linked to scattering, not spin polarisation.

Scattering length from magnetic focusing matches Shubnikov-de Haas results.

Scattering effects must be considered in spin polarisation analysis.

Abstract

In 2D systems with a spin-orbit interaction, magnetic focussing can be used to create a spatial separation of particles with different spin. Here we measure hole magnetic focussing for two different magnitudes of the Rashba spin-orbit interaction. We find that when the Rashba spin-orbit magnitude is large there is significant attenuation of one of the focussing peaks, which is conventionally associated with a change in the spin polarisation. We instead show that in hole systems with a $k^3$ spin-orbit interaction, this peak suppression is due to a change in the scattering of one spin state, not a change in spin polarisation. We also show that the change in scattering length extracted from magnetic focussing is consistent with results obtained from measurements of Shubnikov-de Haas oscillations. This result suggests that scattering must be considered when relating focussing peak amplitude to spin polarisation in hole systems