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.
@article{arxiv.1212.4845,
title = {Layer-by-layer entangled spin-orbital texture of the topological surface state in Bi2Se3},
author = {Z. -H. Zhu and C. N. Veenstra and G. Levy and A. Ubaldini and P. Syers and N. P. Butch and J. Paglione and M. W. Haverkort and I. S. Elfimov and A. Damascelli},
journal= {arXiv preprint arXiv:1212.4845},
year = {2013}
}
Comments
5 pages, 4 figures. A high-resolution version with supplementary material can be found at: http://www.phas.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Articles/BiSe_P.pdf