Kutnyakhov, D.; Chernov, S.; Medjanik, K.; Wallauer, R.; Tusche, C.; Ellguth, M.; Nepijko, S.A.; Krivenkov, M.; Braun, J.; Borek, S.; Minar, J.; Ebert, H.; Elmers, H.J.; Schoenhense, G.: Spin texture of time-reversal symmetry invariant surface states on W(110). Scientific Reports 6 (2016), p. 29394/1-7
10.1038/srep29394
Open Accesn Version

Abstract:
We find in the case of W(110) previously overlooked anomalous surface states having their spin locked at right angle to their momentum using spin-resolved momentum microscopy. In addition to the well known Dirac-like surface state with Rashba spin texture near the -point, we observe a tilted Dirac cone with circularly shaped cross section and a Dirac crossing at 0.28 ×   within the projected bulk band gap of tungsten. This state has eye-catching similarities to the spin-locked surface state of a topological insulator. The experiments are fortified by a one-step photoemission calculation in its density-matrix formulation.