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, Akari Takayama, T. Sato, T. Takahashi, K. Eto, Kouji Segawa, Yoichi Ando

Research output: Contribution to journalArticle

33 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
Externally publishedYes

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Spin polarization
Fermi surface
Photoemission
Fermi surfaces
photoelectric emission
insulators
Surface states
polarization
Photoelectron spectroscopy
data structures
Cones
Tuning
quantitative analysis
cones
tuning
Chemical analysis
spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Relationship between Fermi surface warping and out-of-plane spin polarization in topological insulators : A view from spin- and angle-resolved photoemission. / Nomura, M.; Souma, S.; Takayama, Akari; Sato, T.; Takahashi, T.; Eto, K.; Segawa, Kouji; Ando, Yoichi.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 89, No. 4, 045134, 27.01.2014.

Research output: Contribution to journalArticle

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AU - Sato, T.

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AU - Eto, K.

AU - Segawa, Kouji

AU - Ando, Yoichi

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