Wozniak, Tomasz and Faria, Paulo E. and Seifert, Gotthard and Chaves, Andrey and c, Jens (2020) Exciton g factors of van der Waals heterostructures from first-principles calculations. PHYSICAL REVIEW B, 101 (23): 235408. ISSN 2469-9950, 2469-9969
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External fields are a powerful tool to probe optical excitations in a material. The linear energy shift of an excitation in a magnetic field is quantified by its effective g factor. Here we show how exciton g factors and their sign can be determined by converged first-principles calculations. We apply the method to monolayer excitons in semiconducting transition metal dichalcogenides and to interlayer excitons in MoSe2/WSe2 heterobilayers and obtain good agreement with recent experimental data. The precision of our method allows us to assign measured g factors of optical peaks to specific transitions in the band structure and also to specific regions of the samples. This revealed the nature of various, previously measured interlayer exciton peaks. We further show that, due to specific optical selection rules, g factors in van der Waals heterostructures are strongly spin and stacking-dependent. The calculation of orbital angular momenta requires the summation over hundreds of bands, indicating that for the considered two-dimensional materials the basis set size is a critical numerical issue. The presented approach can potentially be applied to a wide variety of semiconductors.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | INTERLAYER EXCITONS; OPTICAL-PROPERTIES; QUASI-PARTICLE; BERRY PHASE; POLARIZATION; ABSORPTION; |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics > Chair Professor Richter > Group Jaroslav Fabian |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 22 Mar 2021 07:52 |
| Last Modified: | 22 Mar 2021 07:52 |
| URI: | https://pred.uni-regensburg.de/id/eprint/44423 |
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