Excitonic exchange splitting and effects of point-defects on the optical properties in transition metal dichalcogenides (TMDs) nanoribbon*

We assess the spin-orbit coupling (SOC) effects on the optical properties, especially the excitonic exchange splitting [1] of transition metal dichalcogenide (TMDs) nanoribbons [2] using the ab initio GW-Bethe-Salpeter (BSE) approximation. We also investigate how point-defect chalcogen vacancies [3] alter the optical response of flat and bent TMDs nanoribbons of various widths. We present some new exciton features as results of the transitions between defect states and edge states of the nanoribbons. The SOC effects in TMD nanoribbons are involved in the formation of bound excitons, which may open the door for possibilities of spintronics applications of TMD nanoribbons.

[1] M. Palummo et al., Phys. Rev. B 81, 121303(R), (2010) 

[2] H. Tang, et al. arXiv preprint arXiv:2109.04551 (2021) 

[3] S. Refaely-Abramson et al., Phys. Rev. Lett. 121, 167402 (2018)