Time: 09:30 am (UTC/GMT+08:00, Beijing/Shanghai), Jul. 15 (Wedn.), 2020

Online Meeting Room (zoom.com):  Click here to join the meeting

Meeting ID: 988 2141 6246

Speaker: Prof. Chao-Xing Liu (PSU)

Abstract:

In topological materials with Dirac equation as low energy effective theory, the strain can normally play the role of pseudo-gauge field. In this talk, we will show this pseudo-gauge field can give rise to topological piezo-electromagnetic response. In particular, we will discuss two examples. First, we consider a Dirac type of topological phase transition in a 2D crystal and find that the piezo-electric coefficient will exhibit a discontinuous change across the phase transition due to the change of local Berry curvature. Second, we consider the axion charge density wave phase in the 3D time reversal invariant Weyl semimetals and show that the dynamical strain can induce a topological dynamical piezo-magnetic response.