Electronic phonon induced magnetism in moir\'e Mott-Wigner crystals

TL;DR

This paper demonstrates that electronic phonons can induce magnetism in moiré Mott-Wigner crystals without spin interactions, driven by Berry phase effects, and suggests control via chiral phonon photoexcitation.

Contribution

It reveals a novel mechanism of magnetism induced by electronic phonons and Berry phase effects in moiré crystals, independent of traditional spin interactions.

Findings

Electronic phonons induce magnetism in moiré Mott-Wigner crystals.

Berry phase causes valley polarization and spontaneous magnetization.

Magnetism can be engineered through chiral phonon photoexcitation.

Abstract

We show that magnetism in moir\'e Mott-Wigner crystals can be induced by the collective vibration of electrons around their equilibrium positions (i.e., electronic phonons), even without spin interactions between electrons. Due to a geometric valley-orbit coupling from the Berry phase effect, the zero-point energy of electronic phonons reaches minimum when electrons are fully valley polarized. This leads to a spontaneous magnetization when below a critical temperature. We also propose to engineer the magnetism through the photoexcitation of chiral electronic phonons.