Cooperative evolution of intraband and interband excitations for high-harmonic generation in strained MoS2

Modulating electronic structure of two-dimensional materials represents an exciting avenue for tailoring their optoelectronic properties. Here, we identify a strain-induced, cooperative effect of intraband and interband excitations contributing to high-harmonic generation (HHG) in prototype dichalcogenide MoS2 monolayer. We find that besides the dominant intraband contributions, interband current is also indispensable in modulating HHG. The HHG yields increase linearly with the compressive strain since flatter band dispersion and Berry curvature enhance both interband and intraband dynamics. Band structure can be retrieved with high reliability by monitoring the strain-induced evolution of HHG spectra, suggesting that strain not only provides an additional knob to control HHG in solids, but also marks a way towards a complete understanding of underlying microscopic mechanisms.