Spin-orbit interaction and Dirac cones ind-orbital noble metal surface states

Abstract

Band splittings, chiral spin polarization and topological surface states generated by spin-orbit interactions at crystal surfaces are receiving a lot of attention for their potential device applications as well as fascinating physical properties. Most studies have focused on sp states near the Fermi energy, which are relevant for transport and have long lifetimes. Far less explored, though in principle stronger, are spin-orbit interaction effects within d states, including those deep below the Fermi energy. Here, we report a joint photoemission/ab initio study of spin-orbit effects in the deep d orbital surface states of a 24-layer Au film grown on Ag(111) and a 24-layer Ag film grown on Au(111), singling out a conical intersection (Dirac cone) between two surface states in a large surface-projected gap at the time-reversal symmetric M points. Unlike the often isotropic dispersion at Γ point Dirac cones, the M point cones are strongly anisotropic. An effective k · p Hamiltonian is derived to describe the anisotropic band splitting and spin polarization near the Dirac cone.

Clean Ir(111) and Pt(111) electronic surface states: A first-principle fully relativistic investigation

“…The 10 E peaks match the energy position of the states 10 8 S state has been seen by ARPES and studied in detail in Au(111). [37] A similar Dirac cone is predicted also in Pt(111).…”

Spin-split bands of metallic hydrogenated ZnO (101¯) surface: First-principles study

“…[35][36][37][38] In our past study, we clarified that the ZnO (1010) surface belongs to the symmetry point group C s , where the mirror reflections in operation in this symmetry transform (x, y, z) to (−x, y, z). 22 In this case, SOI can be expressed as 22…”

Energy-momentum mapping ofd-derived Au(111) states in a thin film

“…The L-gap Shockley surface state, near E F at  ̅ , and the S2 state, laying 8 eV below it, have similar Rashba-Bychkov-type spin-splitting [20,34], which is not resolved in the present dataset. The properties of the S8 surface state have been described in detail in our previous work [49]. All other surface features along  ̅ -M ̅ are resonances.…”