| Autor: |
Gilliot, Pierre, Gallart, Mathieu, Hönerlage, Bernd |
| Rok vydání: |
2019 |
| Předmět: |
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| Druh dokumentu: |
Working Paper |
| Popis: |
In order to discuss the exciton fine-structure of transition-metal dichalcogenides mono-layers, excitons are first defined in the subspace of electron- and hole states, including the lowest conduction band (LCB) and the uppermost valence band (UVB). Both bands are spin degenerate at the Gamma-point. All other states are neglected. The resulting exciton states are analyzed in the framework of an invariant expansion of a model Hamiltonian: The spin-orbit coupling in the conduction- and valence band is simulated by introducing a fictive magnetic field, giving rise to a splitting of the electron- and hole states outside the $\Gamma$-point. Then the electron-hole exchange-interaction is introduced into the exciton Hamiltonian. It is due to the fact that electron and hole are indistinguishable particles in the exciton problem. In D3h crystal symmetry this electron-hole exchange-interaction has two different contributions: While a first term accounts for an energy re-normalization of all exciton states, a second term does not influence the optical active (spin-singlet) states but affects only the optical inactive (spin-triplet) states, which become mixed in-between the different exciton series. |
| Databáze: |
arXiv |
| Externí odkaz: |
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