Gate-tunable chiral phonons in low-buckled group-IVA monolayers

Hanyu Wang; Zhichao Zhou; Hao Chen; Chongqun Xia; Lifa Zhang; Xiao Li

doi:10.1088/1361-648X/abfee5

Gate-tunable chiral phonons in low-buckled group-IVA monolayers

J Phys Condens Matter. 2021 Jun 3;33(28). doi: 10.1088/1361-648X/abfee5.

Authors

Hanyu Wang^{1

2}, Zhichao Zhou¹, Hao Chen^{1

2}, Chongqun Xia^{1

2}, Lifa Zhang^{1

2}, Xiao Li^{1

2}

Affiliations

¹ School of Physics and Technology, Nanjing Normal University, Nanjing 210023, People's Republic of China.
² Center for Quantum Transport and Thermal Energy Science (CQTES), NNU-SULI Thermal Energy Research Center (NSTER), Nanjing Normal University, Nanjing 210023, People's Republic of China.

PMID: 33962406
DOI: 10.1088/1361-648X/abfee5

Abstract

We investigate the electric response of chiral phonons on the low-buckled group-IVA monolayers by performing first-principles calculations. The vertical electric field breaks the degeneracy of phonon modes at high-symmetry ±Kpoints of the phonon Brillouin zone, and the size of the phononic gap is proportional to the strength of the electric field. The gapped phonon modes at ±Kpossess chiralities with considerable phonon circular polarizations and discrete phonon pseudoangular momenta. The chiralities of phonons are robust against the variation of the field strength, but reversed by changing the field direction. Electric control of chiral phonons adds a new dimension to the study of chiral phonons, which has potential use in the design of phononic and valley devices.

Keywords: chiral phonons; first-principles calculations; gate control.