Research Progress

Weyl phonons in chiral crystals

SourceSeminar Aug 24,2023
Chirality is an indispensable concept that pervades fundamental science and nature, manifesting itself in diverse forms, e.g., quasiparticles, and crystal structures. Of particular interest are Weyl phonons carrying specific Chern numbers and chiral phonons doing circular motions. Up to now, they have been studied independently and the interpretations of chirality seem to be different in these two concepts, impeding our understanding. 
Recently, Tiantian Zhang 's research group at the Institute of Theoretical Physics, Chinese Academy of Sciences demonstrate that they are entangled in chiral crystals. Employing a typical chiral crystal of elementary tellurium (Te) as a case study, the researchers expound on the intrinsic relationship between Chern number of Weyl phonons and pseudoangular momentum (PAM, lph) of chiral phonons. The researchers propose Raman scattering as a new technique to demonstrate the existence of Weyl phonons in Te, by detecting the chirality-induced energy splitting between the two constituent chiral phonon branches for Weyl phonons. Moreover, they also observe the obstructed phonon surface states for the first time.


Tiantian Zhang