Nondegenerate Metallic States on Bi(114): A One-Dimensional Topological Metal

Abstract

The (114) surface of the semimetal Bi is found to support a quasi-one-dimensional, metallic surface state. As required by symmetry, the state is degenerate along the Gamma-Y line of the surface Brillouin zone with a highest binding energy of approximately 150 meV. In the Gamma-X direction the degeneracy is lifted by the strong spin-orbit splitting in Bi, as directly shown by spin-resolved photoemission. This results in a Fermi contour consisting of two closely separated, parallel lines of opposite spin direction. It is argued that similar states on related insulators would give rise to a one-dimensional quantum spin Hall effect.

Colloquium: Topological band theory

“…Th: Si 2014 Bi Th: Murakami 2006, Wada 2011Exp: Jnawali 2012, Hirayama 2011, Hirahara 2012, Wells 2009, Lükermann 2012, Coelho 2013, Chun-Lei 2013, Lu 2015, Takayama 2015Sb Th: Zhang 2012Exp: Yao 2013, Bian 2011 BiTeX (X=I, Br, Cl) Th: HgTe/CdTe Th: Bernevig 2006, Khaymovich 2013Exp: König 2007, Brüne 2012, Nowack 2013, Zholudev 2012, Gusev 2014, Hart 2014 * In the interest of brevity, only the last name of the first author is given. However, in cases of multiple references with the same name and year, titles of the articles should allow the reader to access the appropriate literature.…”

Topology of spin polarization of the 5dstates on W(110) and Al/W(110) surfaces

“…5, and a more complex so-called "topological metal" state was found on Bi(114), Ref. 6, and Sb(111), Ref. 7, which has been related to the topological surface states of topological insulators.…”

Giant spin rotation under quasiparticle-photoelectron conversion: Joint effect of sublattice interference and spin-orbit coupling

“…We emphasize that this is impossible for simple lattices, where ͗ŝ͘ 2 = 1 is maintained either by in-plane polarization 15 or by out-of-plane spin rotation, as recently reported. 16 While the effect of sublattice interference on the angular dependence of ARPES, unveiled by Shirley et al, 13 is well documented for monolayer 10,12 and bilayer 12,17 graphene and for graphite, 13,[18][19][20] the recent progress in studying quasiparticles by SARPES techniques, the novelty of results, and the large magnitude of spin-orbit coupling found in a number of systems 10,16,[21][22][23][24][25][26][27][28][29] all call for proper understanding of interference-generated spin patterns in photoemission. They are specific for the single-step transformation of Bloch spinors of quasiparticles into photoelectron plane waves with large in-plane ͑Brillouin͒ momentum and manifest themselves in singular k dependencies in the k → 0 limit.…”