Relativistic effects and fully spin-polarized Fermi surface at the Tl/Si(111) surface

TL;DR

This study investigates the relativistic electronic structure and complex spin polarization of the Tl/Si(111) surface, revealing fully spin-polarized electron pockets with intricate spin textures near the Fermi surface.

Contribution

First-principles calculations uncover fully spin-polarized surface states with complex momentum-dependent spin textures on Tl/Si(111).

Findings

Existence of fully spin-polarized electron pockets.

Complex spin polarization structure in reciprocal space.

Spin polarization reverses between different electron pockets.

Abstract

We present a detailed analysis of the relativistic electronic structure and the momentum dependent spin-polarization of the Tl/Si(111) surface. Our first principle calculations reveal the existence of fully spin-polarized electron pockets associated to the huge spin-splitting of metallic surface bands. The calculated spin-polarization shows a very complex structure in the reciprocal space, strongly departing from simple theoretical model approximations. Interestingly, the electronic spin-state close to the Fermi surface is polarized along the surface perpendicular direction and reverses its orientation between different electron pockets.