Relativistic splitting of surface states at Si-terminated surfaces of the layered intermetallic compounds RT2 Si2 (R=rare earth; T=Ir, Rh)

Abstract

We present an effective model for surface states at the Si-terminated (001) surface of ternary rare earth (R) intermetallic compounds RT2Si2 with the transition metal element T = Ir or Rh. The model is based on a fully ab initio derivation of the relativistic k⋅p Hamiltonian and is thereby capable of accurately reproducing the spin polarization of the spin-orbit split surface states, which is very different from the classical Rashba effect. The reliable treatment of spin in our model enables a predictive analysis of the effect of magnetic exchange interaction of the surface-state electrons with ferromagnetically ordered 4f moments of the subsurface rare-earth layer in the magnetic phases of the RT2Si2 compounds.