Layer-by-layer entangled spin-orbital texture of the topological surface   state in Bi2Se3
  We study Bi2Se3 by polarization-dependent angle-resolved photoemission spectroscopy (ARPES) and density-functional theory slab calculations. We find that the surface state Dirac fermions are characterized by a layer-dependent entangled spin-orbital texture, which becomes apparent through quantum interference effects. This explains the discrepancy between the spin polarization from spin-resovled ARPES - ranging from 20 to 85% - and the 100% value assumed in phenomenological models. It also suggests a way to probe the intrinsic spin texture of topological insulators, and to continuously manipulate the spin polarization of photoelectrons and photocurrents all the way from 0 to +/-100% by an appropriate choice of photon energy, linear polarization, and angle of incidence. 
Z.-H. Zhu, C.N. Veenstra, G. Levy, A. Ubaldini, P. Syers, N.P. Butch,   J. Paglione, M.W. Haverkort, I.S. Elfimov, and A. Da...
cond-mat.mtrl-sci cond-mat.mes-hall cond-mat.str-el