Giant Rashba-type spin splitting at polar surfaces of BiTeI
S. V. Eremeev+*, I. A. Nechaev*×, E. V. Chulkov×∇
+Institute of Strength Physics and Materials Science SB RAS, 634021 Tomsk, Russia
*Tomsk State University, 634050 Tomsk, Russia
×Donostia International Physics Center, 20018 San Sebastián, Basque Country, Spain
∇Departamento de Fisica de Materiales UPV/EHU, 20080 San Sebastián, Basque Country, Spain
Abstract
On the basis of relativistic ab-initio
calculations, we show that both Te- and I-terminated surfaces of the
polar layered semiconductor BiTeI hold surface states with a giant
Rashba-type spin splitting. The Te-terminated surface state has
nearly isotropic free-electron-like dispersion with a positive
effective mass, which along with the giant spin splitting makes
BiTeI fulfilling the requirements demanded by many
semiconductor-spintronics applications. The I-terminated surface
state with its negative effective-mass dispersion reproduces nicely
the situation with the Rashba-split surface state on surfaces of
noble-metal based surface alloys. The crucial advantage of BiTeI as
compared with the surface alloys is the location of the I-terminated
surface state in a quite wide band gap.