on h-BN*

Transition metal dichalcogenides (TMDs) are of great interest due to a thickness dependent indirect to direct bandgap transition, large spin-orbit coupling, and spin-valley locking. In monolayer limit the TMDs have strong Coulomb interactions due to poor dielectric screening, resulting in strongly bound excitons. Interestingly, the electronic, optical and spin-valley related properties of TMDs can be tuned by surrounding dielectric environment and adatom doping due to many-body effects. We investigated the electronic band structure of single-layer (SL) WS₂ on h-BN by angle-resolved photoemission (ARPES) with spatial resolution of 10μm sized spatial resolution of the μARPES endstation at the MAESTRO facility of the Advanced Light Source. We will discuss the effect of screening and ad-atom spin-orbit coupling on the trionic quasiparticles in the spectral function of SL WS₂. Upon electron doping via alkali metal we observed giant spin-orbit splitting and bandgap renormalization in SL WS₂.