1. Ultrafast many-body bright-dark exciton transition in anatase TiO2.
- Author
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Aolei Wang, Xiang Jiang, Qijing Zheng, Petek, Hrvoje, and Jin Zhao
- Subjects
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TITANIUM dioxide , *BOSE-Einstein condensation , *BETHE-Salpeter equation , *QUANTUM information science , *BAND gaps , *SEMICONDUCTOR industry - Abstract
The momentum-forbidden dark excitons can have a pivotal role in quantum information processing, Bose-Einstein condensation, and light-energy harvesting. Anatase TiO2 with an indirect band gap is a prototypical platform to study bright to momentum-forbidden dark exciton transition. Here, we examine, by GW plus the real-time Bethe-Salpeter equation combined with the nonadiabatic molecular dynamics (GW + rtBSE-NAMD), the many-body transition that occurs within 100 fs from the optically excited bright to the strongly bound momentum-forbidden dark excitons in anatase TiO2. Comparing with the single-particle picture in which the exciton transition is considered to occur through electron-phonon scattering, within the GW + rtBSE-NAMD framework, the many-body electron-hole Coulomb interaction activates additional exciton relaxation channels to notably accelerate the exciton transition in competition with other radiative and nonradiative processes. The existence of dark excitons and ultrafast bright-dark exciton transitions sheds insights into applications of anatase TiO2 in optoelectronic devices and light-energy harvesting as well as the formation process of dark excitons in semiconductors. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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