Chiral phonon induced spin polarization

Abstract

The current understanding of chirality suggests the existence of a connection between structure and angular momentum, including spin. This is particularly emphasized 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 adding to the total moment. Here, it is shown that chiral phonons may induce a nontrivial spin texture in an otherwise nonmagnetic electronic structure. By considering a setup in which electrons and phonons are interfaced with each other, it is shown that chiral phonons may transfer their 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.