2020/01/22 by J. Jadczak, Jadczak, Joanna, Joanna Kutrowska-Girzycka +23
Engineering · Materials Science · #2D Materials and Applications #FOS: Physical sciences #MXene and MAX Phase Materials #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Perovskite Materials and Applications
paper · pdf · doi:10.48550/arxiv.2001.07929
openalex publication_date 2020/01/22 · openalex created_date 2020/07/23 · openalex updated_date 2026/07/28
We present experimental and theoretical results on the high-quality single-layer MoS2 which reveal the fine structure of charged excitons, i.e., trions. In the emission spectra we resolve and identify two trion peaks, T1 and T2, resembling the pair of singlet and triplet trion peaks (TS and TT) in tungsten-based materials. However, in polarization-dependent photoluminescence measurements we identify these peaks as novel intra- and inter-valley singlet trions, constituting the trion fine structure distinct from that already known in bright and dark 2D materials with large conduction-band splitting induced by the spin-orbit coupling. We show that the trion energy splitting in MoS2 is a sensitive probe of inter- and intra-valley carrier interaction. With additional support from theory we claim that the existence of these singlet trions combined with an anomalous excitonic g-factor and the characteristic temperature dependence of the emission spectra together suggest that monolayer MoS2 has a dark excitonic ground state, despite having "bright" single-particle arrangement of spin-polarized conduction bands.