Orbital-symmetry-selective spin characterization of Dirac-cone-like state on W(110)

• Published in: Physical review. B 2016-04, Vol.93 (16), Article 161403
• Main Authors: Miyamoto, K., Wortelen, H., Mirhosseini, H., Okuda, T., Kimura, A., Iwasawa, H., Shimada, K., Henk, J., Donath, M.
• Format: Article
• Language: English
• Subjects: Degrees of freedom; Excitation; Mathematical analysis; Orbitals; Surface layer; Symmetry; Texts; Texture
• ISSN: 2469-9950; 2469-9969
• DOI: 10.1103/PhysRevB.93.161403

The surface of W(110) exhibits a spin-orbit-induced Dirac-cone-like surface state, which is of mainly d sub(z2) orbital character near (ProQuest: Formulae and/or non-USASCII text omitted), although it is strongly influenced by the twofold C sub(2v) surface symmetry. Its distinctive k-dependent spin polarization along (ProQuest: ... denotes formulae and/or non-USASCII text omitted) is revealed by spin- and angle-resolved photoemission excited with p- and s-polarized light. The spin texture of the surface state is found to change sign upon switching from p- to s-polarized light. Based on electronic-structure calculations, this behavior is explained by the orbital composition of the Dirac-cone-like state. The dominant part of the state has even mirror symmetry and is excited by p-polarized light. A minor part with odd symmetry is excited by s-polarized light and exhibits a reversed spin polarization. Our study demonstrates in which way spin-orbit interaction combines the spin degree of freedom with the orbital degree of freedom and opens a way to manipulate the spin information gathered from the Dirac-cone-like surface state by light. Our results prove that "spin control" is not restricted to topological surface states with p-type orbital symmetry in topological insulators.