Relationship between Fermi surface warping and out-of-plane spin polarization in topological insulators: A view from spin- and angle-resolved photoemission

M. Nomura, S. Souma, A. Takayama, T. Sato, T. Takahashi, K. Eto, Kouji Segawa, Yoichi Ando

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

We have performed spin- and angle-resolved photoemission spectroscopy of the topological insulator Pb(Bi,Sb)2Te4 and observed significant out-of-plane spin polarization on the hexagonally warped Dirac-cone surface state. To put this into context, we carried out quantitative analysis of the warping strengths for various topological insulators [Pb(Bi,Sb)2Te4, Bi2Te3, Bi2Se3, and TlBiSe2] and elucidated that the out-of-plane spin polarization Pz is systematically correlated with the warping strength. However, the magnitude of Pz is found to be only half that expected from the k·p theory when the warping is strong. Besides confirming a universal relationship between the spin polarization and the surface state structure, our data provide an empirical guiding principle for tuning the spin polarization in topological insulators.

Original languageEnglish
Article number045134
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume89
Issue number4
DOIs
Publication statusPublished - 2014 Jan 27

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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