Band gap renormalization in doped transition-metal dichalcogenide heterostructures*

Transition-metal dichalcogenide (TMD) heterostructures have attracted broad interests as a playground for studying the light-matter interactions and valleytronics in low-dimensional semiconductors. Meanwhile, the carrier density in two-dimensional systems can be conveniently tuned by external gates, thus providing a controlling knob for manipulating their electronic properties. In this work, we employ the first-principles many-body perturbation theory to study the band gap renormalization in carrier-doped TMD heterobilayers. Because of the coupling between the carrier plasmon and quasiparticle excitations, a significant band gap renormalization of a few hundreds of meV is predicted. This band-gap renormalization further significantly affects the band alignment. Our work provides a guidance for experiments on band gap engineering in van der Waals heterostructures.