Tuning the electronic properties of WS$_{\mathrm{2}}$ on hBN by adatom engineering

Among transition metal dichalogenides (TMDs), monolayer tungsten disulfide (WS$_{\mathrm{2}})$ is gaining interest due to its large band gap, relatively high charge carrier mobilites and high spin-orbit coupling. The possibility to tune the electronic, optical and spin-valley related properties by substrate and adatom (e.g. alkali and heavy metal doping) engineering are one of the most interesting yet unexplored areas of research in the field of TMDs. Recently, we investigated the electronic band structure of monolayer WS$_{\mathrm{2}}$ on h-BN by angle-resolved photoemission (ARPES). The 10$\mu $m sized spatial resolution of the $\mu $ARPES endstation at the newly commissioned MAESTRO facility of the Advanced Light Source allowed us to identify these flakes and to obtain high quality band structure and core level information in a full spectro-microscopic approach. As particularly interesting finding we will discuss the effect of alkali and heavy metal doping on the spin-orbit coupling in the valence band of WS$_{\mathrm{2}}$ on h-BN.