Spin-orbit splitting in an anisotropic two-dimensional electron gas

Abstract

In the conventional Rashba model for an isotropic two-dimensional electron gas ͑2DEG͒, the electrons are spin-orbit split by a structural inversion asymmetry ͑SIA͒ perpendicular to the confinement plane. An additional SIA within the confinement plane leads to another contribution to the spin-orbit interaction which is investigated by means of a nearly-free electron model. The interplay of both contributions manifests itself as an enhanced splitting in the anisotropic 2DEG, as compared to the isotropic case. Further, the spin polarization of the electronic states is rotated out of the confinement plane. Both findings corroborate recent experimental and theoretical results for the ordered surface alloys Bi/ Ag͑111͒ and Pb/ Ag͑111͒.

Quantitative vectorial spin analysis in angle-resolved photoemission:Bi∕Ag(111)andPb∕Meier1, Dil2, Lobo-Checa3 et al. 2008Phys. Rev. B15415731View full textAdd to dashboardCite

“…It was qualitatively shown in a nearly free electron (NFE) model calculation [22], that this enhancement is due to a further reduction of the symmetry compared to the sole presence of the surface, caused by an additional in plane inversion asymmetry. In the surface alloys Bi/Ag(111) and Pb/Ag(111), the in plane symmetry is altered due to the ( √ 3 × √ 3)R30 o surface reconstruction and the in-plane potential is modulated, as there are comparably light atoms (Ag) surrounding heavier atoms (Bi or Pb).…”

Ab initioelectronic structure of thallium-based topological insulators

“…Moreover, we notice a small polarization component in the z direction, which results from the in-plane potential gradients arising from the threefold symmetry of the structure. 41 This polarization is energy dependent and is manisfested in the spin-vector deviation from the xy plane: the angle between the spin direction and the plane is equal to 21 • , 39 • , and 32 • for the energy cuts of 90, 140, and 190 meV, respectively.…”

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

“…[6][7][8][9][10] It is now well established that the origin of the surface electron spin-splitting resides on the lack of the inversion symmetry close to the surface area. Interestingly, recent model calculations 11,12 suggest the important role played by the in-plane inversion asymmetry in the enhancement of the spin-splitting magnitude, as well as in the determination of the spin-polarization structure.…”