Dirac cone with helical spin polarization in ultrathin $\alpha$-Sn(001) films

Yoshiyuki Ohtsubo; Patrick Le Fèvre; François Bertran; Amina Taleb-Ibrahimi

doi:10.1103/PhysRevLett.111.216401

Dirac cone with helical spin polarization in ultrathin $\alpha$-Sn(001) films

Mesoscale and Nanoscale Physics 2013-11-22 v2

Authors: Yoshiyuki Ohtsubo , Patrick Le Fèvre , François Bertran , Amina Taleb-Ibrahimi

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Abstract

Spin-split two-dimensional electronic states have been observed on ultrathin Sn(001) films grown on InSb(001) substrates. Angle-resolved photoelectron spectroscopy (ARPES) performed on these films revealed Dirac-cone-like linear dispersion around the $\bar{\Gamma}$ point of surface Brillouin zone, suggesting nearly massless electrons belonging to 2D surface states. The states disperse across a bandgap between bulk-like quantum well states in the films. Moreover, both circular dichroism of ARPES and spin-resolved ARPES studies show helical spin polarization of the Dirac-cone-like surface states, suggesting a topologically protected character as in a bulk topological insulator (TI). These results indicate that a quasi-3D TI phase can be realized in ultrathin films of zero-gap semiconductors.

Keywords

dirac cone helical spin polarization ultrathin films $\alpha$-sn arpes topological insulator surface states zero-gap semiconductor

Cite

@article{arxiv.1309.5917,
  title  = {Dirac cone with helical spin polarization in ultrathin $\alpha$-Sn(001) films},
  author = {Yoshiyuki Ohtsubo and Patrick Le Fèvre and François Bertran and Amina Taleb-Ibrahimi},
  journal= {arXiv preprint arXiv:1309.5917},
  year   = {2013}
}

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4 main figures and 5 figures for supplemental material

Dirac cone with helical spin polarization in ultrathin $\alpha$-Sn(001) films

Abstract

Keywords

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