Abstract
Lattice deformations act on the low-energy excitations of Dirac materials as effective axial vector fields. This allows to directly detect quantum anomalies of Dirac materials via the response to axial gauge fields. We investigate the parity anomaly in Dirac nodal line semimetals induced by lattice vibrations, and establish a topological piezoelectric effect; i.e., periodic lattice deformations generate topological Hall currents that are transverse to the deformation field. The currents induced by this piezoelectric effect are dissipationless and their magnitude is completely determined by the length of the nodal ring, leading to a semi-quantized transport coefficient. Our theoretical proposal can be experimentally realized in various nodal line semimetals, such as CaAgP and Ca$_{_3}$P${_2}$.
Highlights
Over the past few years a number of new types of topological semimetals have been discovered [1,2,3,4,5,6,7]
We investigate the parity anomaly in Dirac nodal line semimetals induced by lattice vibrations and establish a topological piezoelectric effect; that is, periodic lattice deformations generate topological Hall currents that are transverse to the deformation field
We have shown that dynamical strain induces a topological piezoelectric effect (TPEE) in nodal-line semimetals (NLSMs), which manifests itself by dissipationless Hall currents, originating from the parity anomaly
Summary
Over the past few years a number of new types of topological semimetals have been discovered [1,2,3,4,5,6,7]. Two-dimensional Dirac materials, such as graphene, are described by quantum field theories with parity anomalies, which break space-time inversion symmetry [8,9]. The electromagnetic responses of these nodal rings are given by Chern-Simons actions, which break parity symmetry These Chern-Simons terms lead to transverse Hall effects, where electrons from opposite sides of the nodal ring flow to opposite surfaces, when an electric field is applied [47]. We derive a low-energy description of NLSMs in the presence of strain and show that periodic lattice deformations generate a topological piezoelectric effect (TPEE), which originates from the parity anomaly This piezoelectric effect manifests itself by dissipationless Hall currents that are transverse to the deformation field. Where S is the area encircled by the nodal ring projected onto the surface Brillouin zone
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
