“School of Physic”
Back to Papers HomeBack to Papers of School of Physic
| Paper IPM / Physic / 16605 |
|
||||||
| Abstract: | |||||||
|
The quasiparticle band-gap renormalization(BGR) induced by the doped carriers is an important and well-known feature in two-dimensional (2D) semiconductors including transition metal dichalcogenides (TMDs) and it is of both theoretical and practical interest. To get a quantitative understanding of this effect, here we calculate the quasiparticle band-gap renormalization of the electron-doped monolayer MoS2, a prototypical member of TMDs. The many-body electron-electron interaction-induced renormalization of the self-energy is found within random phase approximation (RPA) and to account for the quasi-2D character of the Coulomb interaction in this system a Keldysh-type interaction with nonlocal dielectric constant is used. Considering the renormalization of both the valence and the conduction bands, our calculations reveal a large and nonlinear band-gap renormalization upon adding free carriers to the conduction band. We find a 410 meV reduction of the band-gap for the monolayer MoS2 on SiO2 substrate at the free carrier density n=4.9×1012 cm−2 which is in excellent agreement with available experimental results. We also discuss the role of exchange and correlation parts of the self-energy on the overall band-gap renormalization of the system. The strong dependence of the band-gap renormalization on the surrounding dielectric environment is also demonstrated in this work, and a much larger shrinkage of the band-gap is predicted for the freestanding monolayer MoS2.
Download TeX format |
|||||||
| back to top | |||||||
