Quantitative analysis on electric dipole energy in Rashba band splitting.
We report on quantitative comparison between the electric dipole energy and the Rashba band splitting in model systems of Bi and Sb triangular monolayers under a perpendicular electric field. We used both first-principles and tight binding calculations on p-orbitals with spin-orbit coupling. First-principles calculation shows Rashba band splitting in both systems. It also shows asymmetric charge distributions in the Rashba split bands which are induced by the orbital angular momentum. We calculated the electric dipole energies from coupling of the asymmetric charge distribution and external electric field, and compared it to the Rashba splitting. Remarkably, the total split energy is found to come mostly from the difference in the electric dipole energy for both Bi and Sb systems. A perturbative approach for long wave length limit starting from tight binding calculation also supports that the Rashba band splitting originates mostly from the electric dipole energy difference in the strong atomic spin-orbit coupling regime.
Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Korea.
Jisook
J
Hong
School of Physics, Korea Institute for Advanced Study, Seoul 130-722, Korea.
Jun-Won
JW
Rhim
Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea.
Changyoung
C
Kim
Department of Physics, Incheon National University, Incheon 406-772, Korea.
Seung
S
Ryong Park
Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Korea.|Department of Physics and Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea.
Ji
J
Hoon Shim