Role of symmetry breaking in high-order harmonic generation from Su-Schrieffer-Heeger systems
Chao Ma, Xue-Bin Bian, Tao-Yuan Du
Abstract
High-order harmonic generation (HHG) in topological insulators (TIs) is receiving tremendous attention due to the topologically protected surface states. To study the HHG in topological surface, an open-boundary Su-Schrieffer-Heeger model was adopted and we rigorously addressed quantum decoherence via Lindblad equation. We find that role of the symmetry breaking is significant for HHG in TIs. Our results reveal that (i) the edge electrons in TIs radiate pure even-order harmonics via distinguishing the topological bulk and edge contributions; (ii) a short dephasing time makes the even-order harmonic yields lower than that of odd order; (iii) two-channel subcycle interference model and dynamics-symmetry analysis were developed to explain the odd- and even-order characteristic of HHG spectra; (iv) the symmetry breaking selectively enhances emission of certain channel. This work reveals the vital role of the TIs' symmetry in the strong-field HHG, which provides an alternative way to understand and control the HHG from topological surfaces.