[17p-M_178-1~15] 17.3 Layered materials

2:00 PM - 2:15 PM JST(5:00 AM - 5:15 AM UTC)

[17p-M_178-1] Electric field control of Valley polarization and coherence lifetime in Moiré interlayer exciton

〇Yuto Urano^1,2, Nurul Fariha Ahmad¹, Kenji Watanabe¹, Takashi Taniguchi¹, Daichi Kozawa¹, Ryo Kitaura^1,2 (1.NIMS, 2.Hokkaido Univ.)

Keywords:

2D-semiconductor,Valleytronics,Quantum manipulation technology

Monolayer transition-metal dichalcogenides (TMDs) possess a valley degree of freedom associated with the inequivalent K and K′ valleys, which can be selectively manipulated using optical polarization. However, in monolayer TMDs, valley superpositions rapidly decay on a sub-picosecond timescale due to strong intervalley exchange interactions, severely limiting valley coherence. In contrast, moiré excitons in TMD heterostructures can form zero-dimensional confinement states, where the spatial localization strongly suppresses the intervalley exchange interaction. This suppression is expected to enhance valley relaxation and valley coherence lifetime. In this study, we investigate electrically tunable moiré excitons using dual-gate device structure. By controlling carrier density and vertical electric fields, we modulated the electron-hole distance and aimed more enhancement the valley relaxation and coherence time.