Screening and many-body effects in two-dimensional crystals: MonolayerMoS2
- Resource Type
- Authors
- Steven G. Louie; Diana Y. Qiu; Felipe H. da Jornada
- Source
- Physical Review B. 93
- Subject
- Physics
Condensed Matter - Materials Science
Condensed matter physics
business.industry
Exciton
Ab initio
Materials Science (cond-mat.mtrl-sci)
FOS: Physical sciences
02 engineering and technology
Dielectric
021001 nanoscience & nanotechnology
01 natural sciences
Many body
Semiconductor
Transition metal
0103 physical sciences
Monolayer
Coulomb
010306 general physics
0210 nano-technology
business
- Language
- ISSN
- 2469-9969
2469-9950
We present a systematic study of the variables affecting the electronic and optical properties of two-dimensional (2D) crystals within ab initio $GW$ and $GW$ plus Bethe-Salpeter equation ($GW$-BSE) calculations. As a prototypical 2D transition metal dichalcogenide material, we focus our study on monolayer ${\mathrm{MoS}}_{2}$. We find that the reported variations in $GW$-BSE results in the literature for monolayer ${\mathrm{MoS}}_{2}$ and related systems arise from different treatments of the long-range Coulomb interaction in supercell calculations and convergence of $k$-grid sampling and cutoffs for various quantities such as the dielectric screening. In particular, the quasi-2D nature of the system gives rise to fast spatial variations in the screening environment, which are computationally challenging to resolve. We also show that common numerical treatments to remove the divergence in the Coulomb interaction can shift the exciton continuum leading to false convergence with respect to $k$-point sampling. Our findings apply to $GW$-BSE calculations on any low-dimensional semiconductors.