Spin-orbit–induced spin splittings in polar transition metal dichalcogenide monolayers Y. C. Cheng, Z. Y. Zhu, M. Tahir and U. Schwingenschlögl EPL, 102 5 (2013) 57001 Published online: 13 June 2013 DOI: 10.1209/0295-5075/102/57001