Phonons of electronic crystals in two-dimensional semiconductor moiré patterns

Abstract

We theoretically studied the phonon properties of the triangular-, stripe- and honeycomb-type electronic crystals recently found in two-dimensional semiconductor moiré patterns. By analyzing the phonon dispersions, we found the interaction induced lattice deformation in the zigzag-stripe crystal results in a much higher dynamical stability than in the linear-stripe crystal. Moreover, chiral phonons with finite magnetizations and large Berry curvatures can emerge in triangular and honeycomb crystals under time-reversal or inversion symmetry breaking. The small effective mass of the electrons allows the selective and efficient generation of chiral phonons from the optical activity of zone-center phonons combined with the anharmonicity, facilitating the realization of the phonon Hall effect. These findings point to an exciting new platform for exploring chiral phonons and the related topological phononic devices.

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Cited by in corpus (7)

• Dipolar interactions enhanced by two-dimensional dielectric screening in few-layer van der Waals structures
• Twistronics and moiré superlattice physics in 2D transition metal dichalcogenides
• Melting of electronic and excitonic crystals in 2D semiconductor moiré patterns: a perspective from the Lindemann criterion
• Stability of Wigner crystals and Mott insulators in twisted moiré structures
• Spin-polarized transport properties in magnetic moiré superlattices
• Chiral phonons of honeycomb-type bilayer Wigner crystals
• Electronic phonon-induced magnetism in moiré Mott-Wigner crystals