Bulk and surface Rashba splitting in single termination BiTeCl

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By angle-resolved photoemission spectroscopy (ARPES) we observe a giant Rashba-type spin splitting in the electronic bulk conduction and valence bands of the semiconductor BiTeCl. This material belongs to the group of bismuth tellurohalides BiTeX (X = Cl,Br,I) which are layered non-centrosymmetric materials with strong spin-orbit interaction. By photon energy-dependent ARPES, we separate the bulk and surface contribution of the electronic structure and show that the tellurium-terminated (0001) crystal surface hosts spin-split two-dimensional surface states. On the chlorine-terminated surface at the opposite side of the crystal no surface states are observed due to photon-induced surface chemistry. © IOP Publishing and Deutsche Physikalische Gesellschaft.
This work was supported by the Swiss National Science Foundation and the Ministry of Education and Science of the Russian Federation (grant no. 2.8575.2013).