Non-trivial spin-texture of the coaxial Dirac cones on the surface of topological crystalline insulator SnTe

Understand

We present first principles calculations of the nontrivial surface states and their spin-textures in the topological crystalline insulator SnTe.

• The surface state dispersion on the [001] surface exhibits four Dirac-cones centered along the intersection of the mirror plane and the surface plane.
• We propose a simple model of two interacting coaxial Dirac cones to describe both the surface state dispersion and the associated spin-texture.
• While the out-of-the-plane spin polarization is zero due to the crystalline and time-reversal symmetries, the in-plane spin texture shows helicity with some distortion due to the interaction of the two coaxial Dirac cones, indicating a nontrivial mirror Chern number of -2, distinct from the value of -1 in $Z_{2}$ topological insulator such as Bi/Sb alloys or Bi$_2$Se$_3$.