[7a-A404-1~8] 4.6 Nanocarbon and 2D Materials

▼ [7a-A404-2] Exciton Hall effect and transport of valley exciton in monolayer MoS₂

〇(D)Masaru Onga¹, Yijin Zhang^2,3, Toshiya Ideue¹, Yoshihiro Iwasa^1,4 (1.Univ. of Tokyo, 2.Osaka Univ., 3.Max-Planck-Inst., 4.RIKEN CEMS)

Keywords:exciton, transiton metal dichalcogenide, valleytronics

Monolayer transition metal dichalcogenides exhibit unique optical phenomena owing to the two-dimensional structure and valley degrees of freedom. Many researchers have revealed that excitonic states play an important role in optical response, and have observed the diffusion transport of excitons in this system. Here we report transport phenomena of valley excitons in monolayer MoS₂ at low temperature through polarization-resolved photoluminescence mapping. The observed valley diffusion length reaches as much as 2 um, meaning that valley information pumped by circularly polarized light is preserved in a micrometer-scale. More importantly, we observed valley-contrasting transverse motion of valley excitons under zero magnetic fields, which is the first observation of a new Hall effect of excitonic quasiparticles (exciton Hall effect). These results will open new Hall physics of composite particles and exciton-based valleytronics in two-dimensional materials.