Excitonic structure of the optical conductivity in MoS$_2$ monolayers
| Autor: | Caio H. Lewenkopf, Emilia Ridolfi, Vitor M. Pereira |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Physics
Condensed Matter - Materials Science Condensed matter physics Condensed Matter - Mesoscale and Nanoscale Physics Exciton Ab initio Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences 02 engineering and technology Substrate (electronics) 021001 nanoscience & nanotechnology 01 natural sciences Optical conductivity Brillouin zone Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences Monolayer Absorption (logic) 010306 general physics 0210 nano-technology Electronic band structure |
| Popis: | We investigate the excitonic spectrum of MoS$_2$ monolayers and calculate its optical absorption properties over a wide range of energies. Our approach takes into account the anomalous screening in two dimensions and the presence of a substrate, both cast by a suitable effective Keldysh potential. We solve the Bethe-Salpeter equation using as a basis a Slater-Koster tight-binding model parameterized to fit ab initio MoS$_2$ band structure calculations. The resulting optical conductivity is in good quantitative agreement with existing measurements up to ultraviolet energies. We establish that the electronic contributions to the C excitons arise not from states in the vicinity of the $\Gamma$ point, but from a set of $k$-points over extended portions of the Brillouin zone. Our results reinforce the advantages of approaches based on effective models to expeditiously explore the properties and tunability of excitons in TMD systems. Comment: Published version, 16 pages, 10 figures |
| Databáze: | OpenAIRE |
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