Title

Nonlinear effects in topological materials

Publication Name

Frontiers of Optoelectronics

Abstract

Materials, where charge carriers have a linear energy dispersion, usually exhibit a strong nonlinear optical response in the absence of disorder scattering. This nonlinear response is particularly interesting in the terahertz frequency region. We present a theoretical and numerical investigation of charge transport and nonlinear effects, such as the high harmonic generation in topological materials including Weyl semimetals (WSMs) and α-T systems. The nonlinear optical conductivity is calculated both semi-classically using the velocity operator and quantum mechanically using the density matrix. We show that the nonlinear response is strongly dependent on temperature and topological parameters, such as the Weyl point (WP) separation b and Berry phase ϕ . A finite spectral gap opening can further modify the nonlinear effects. Under certain parameters, universal behaviors of both the linear and nonlinear response can be observed. Coupled with experimentally accessible critical field values of 10 –10 V/m, our results provide useful information on developing nonlinear optoelectronic devices based on topological materials. [Figure not available: see fulltext.] 3 B 4 5

Open Access Status

This publication is not available as open access

Volume

14

Issue

1

First Page

99

Last Page

109

Share

COinS
 

Link to publisher version (DOI)

http://dx.doi.org/10.1007/s12200-020-1088-x