Abstract
The previous research shows that that a binary alloy composed of heavy atoms, Pb and Au, has large Rashba effect, yielding two cones at Γ ̅ and two giant Rashba splitting at M ̅. Experiments and first-principles calculations of the electronic structure indicated that such a Rashba effect may be produced only via a special buckling configuration induced by squeezing from the top Au capping layers and bottom Pb films. In this research, we demonstrated that with Bi as the capping layer on PbAu alloy, the Rashba effect is reproduced as well. This result means that Rashba-splitting band structure of PbAu alloy layer is caused by a capping layer on the top, which breaks the inversion symmetry and enhances the buckling height. We tried to deposit Bi onto PbAu alloy layer at Room temperature and low temperature, T = -130 ˚C, respectively and found that Rashba-splitting band structure only showed up at room temperature. It means that the atoms of capping layer must be at specific locations that are commensurate with Au atoms of alloy. In addition, we found that the binding energy of Rashba-splitting band structure shifted into higher binding energy and dispersion changed, indicating that we can use different kinds of atoms as the capping layer to tune the Rashba effect of the middle alloy.