Fig. 2: Hidden Rashba spin-layer locking in \({\mathcal{I}}\)-Si2Bi2.
From: Unveiling giant hidden Rashba effects in two-dimensional Si2Bi2
Plane-averaged electrostatic potentials and electronic structures near the conduction band minima of an artificially constructed asymmetric 2D SiBi monolayer (a–c) and \({\mathcal{I}}\)-Si2Bi2 (d–f). The respective structures, in which Si and Bi atoms are depicted by the purple and blue spheres, respectively, are overlaid in (a) and (d). The dangling bond of each Si atom in (a) is saturated with a hydrogen atom depicted with the white sphere. The electronic band structures are shown without SOC in (b) and (e), and with SOC in (c) and (f). The latter two cases clearly show the Rashba band splittings, one with the R-1 and the other with the R-2. Local orbital contributions are displayed with skyblue, green, and yellow circles for Si s, Bi s, and pz orbitals, respectively. The radius of circle indicates the degree of the orbital contribution. The ΔEI in (e) indicates the splitting energy between CB1 and CB2 due to the interaction between the top and bottom SLs. The red and blue arrows denote spin states in (c) and (f). (g) Spin textures spatially resolved on the top (left) and bottom (right) Bi SLs, or Bitop and Bibot, plotted on the Rashba bands shown in (f). Red (blue) arrows represent the clockwise (counterclockwise) spin chirality and the colorbox indicates energy scale in eV relative to the bottom of the conduction band.
