Chiral phonons of honeycomb-type bilayer Wigner crystals

TL;DR

This paper theoretically explores how chiral phonons in honeycomb bilayer Wigner crystals can be controlled via symmetry breaking and external fields, offering a tunable platform for studying chiral phononic phenomena.

Contribution

It introduces the concept of tunable chiral phonons in bilayer Wigner crystals, highlighting their dependence on symmetry breaking and external parameters.

Findings

Chiral phonons emerge under inversion symmetry breaking.

Magnetic fields can induce time-reversal symmetry breaking.

Phonon frequencies and chirality are tunable through system parameters.

Abstract

We theoretically investigated the chiral phonons of honeycomb-type bilayer Wigner crystals recently discovered in van der Waals structures of layered transition metal dichalcogenides. These chiral phonons can emerge under the inversion symmetry breaking introduced by an effective mass imbalance between the two layers or a moir\'e potential in one layer, as well as under the time-reversal symmetry breaking realized by applying a magnetic field. Considering the wide tunability of layered materials, the frequencies and chirality values of phonons can both be tuned by varying the system parameters. These findings suggest that bilayer honeycomb-type Wigner crystals can serve as an exciting new platform for studying chiral phonons.