Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle (Saale), Germany.
J Phys Condens Matter. 2010 Sep 29;22(38):385501. doi: 10.1088/0953-8984/22/38/385501. Epub 2010 Sep 3.
By detailed first-principles calculations we show that the Fermi energy and the Rashba splitting in disordered ternary surface alloys Bi(x)Pb(y)Sb(1 - x - y)/Ag(111) can be independently tuned by choosing the concentrations x and y of Bi and Pb, respectively. The findings are explained by three fundamental mechanisms, namely the relaxation of the adatoms, the strength of the atomic spin-orbit coupling, and band filling. By mapping the Rashba characteristics, i.e. the splitting k(R) and the Rashba energy E(R), and the Fermi energy of the surface states in the complete range of concentrations, we find that these quantities depend monotonically on x and y, with a very few exceptions. Our results suggest that we should investigate experimentally effects which rely on the Rashba spin-orbit coupling depending on spin-orbit splitting and band filling.
通过详细的第一性原理计算，我们表明通过分别选择 Bi 和 Pb 的浓度 x 和 y，无序三元表面合金 Bi(x)Pb(y)Sb(1 - x - y)/Ag(111) 的费米能和 Rashba 劈裂可以独立调节。这一发现可以用三个基本机制来解释，即 adatoms 的弛豫、原子自旋轨道耦合的强度和能带填充。通过绘制 Rashba 特征，即劈裂 k(R)和 Rashba 能量 E(R)以及表面态的费米能在整个浓度范围内，我们发现这些量随 x 和 y 的变化而单调变化，只有极少数例外。我们的结果表明，我们应该根据自旋轨道劈裂和能带填充来实验性地研究依赖于 Rashba 自旋轨道耦合的效应。
