Chiral Phonon Induced Spin-Polarization

TL;DR

This paper demonstrates that chiral phonons can transfer angular momentum to electrons, inducing spin polarization in non-magnetic materials, revealing a new mechanism linking phonon chirality to spintronic effects.

Contribution

It introduces a novel mechanism where chiral phonons induce spin polarization in electrons, expanding understanding of phonon-electron interactions in spin physics.

Findings

Chiral phonons can induce spin-texture in non-magnetic electronic structures.

Angular momentum transfer from chiral phonons causes electron spin polarization.

Achiral phonons do not produce the same spin transfer effect.

Abstract

The current understanding of chirality suggests the existence of a connection between structure and angular momentum, including spin. This is particularly emphasised in the chiral induced spin selectivity effect, where chiral structures act as spin filters. However, the recent discovery of chiral phonons have demonstrated that phonons too may carry angular momentum which also can be regarded as magnetic moments which add to the total moment. Here, it is shown that chiral phonons may induce a non-trivial spin-texture in an otherwise non-magnetic electronic structure. By considering a set-up in which electrons and phonons are interfaced with each other, it is shown that chiral phonons may transfer its angular momentum into the electron reservoir which, thereby, becomes spin-polarized. It is, moreover, shown that an equivalent mechanism does not exist whenever the electrons are interfaced with achiral phonons.