Detection of spin polarized currents in quantum point contacts via transverse electron focusing

TL;DR

This paper demonstrates that a transverse electron focusing setup can effectively detect spin-polarized currents generated in quantum point contacts with spin-orbit interaction, providing a practical method for spin polarization measurement.

Contribution

It introduces a simple experimental technique using transverse electron focusing to detect spin polarization in quantum point contacts, highlighting the role of peak asymmetry.

Findings

Focusing peak asymmetry indicates spin polarization.

Method can distinguish spin-polarized currents from unpolarized ones.

Quantum point contact geometry influences detection sensitivity.

Abstract

It has been predicted recently that an electron beam can be polarized when it flows adiabatically through a quantum point contact in a system with spin-orbit interaction. Here, we show that a simple transverse electron focusing setup can be used to detect such polarized current. It uses the amplitude's asymmetry of the spin-split transverse electron focusing peak to extract information about the electron's spin polarization. On the other hand, and depending on the quantum point contact geometry, including this one-body effect can be important when using the focusing setup to study many-body effects in quantum point contacts.