Department of Materials Science and Engineering, Tokyo Institute of Technology, J1-3, 4259 Nagatsuda, Midori-ku, Yokohama 226-8502, Japan.
Phys Rev Lett. 2011 Jul 8;107(2):027204. doi: 10.1103/PhysRevLett.107.027204. Epub 2011 Jul 7.
We studied the quantum interference of electrons in the Bi (p(x), p(y)) orbital-derived j = 1/2 spin-split surface states at Bi/Ag(111)√3 × √3 surfaces of 10 monolayer thick Ag(111) films on Si(111) substrates. Surface electron standing waves were observed clearly at the energy (E) below the intersection of the two spin-split downward dispersing parabola bands (E(x)). The E dependence of the standing wave pattern reveals the dispersion as the average of the two spin-split surface bands due to the interference between |(k + Δ), ↑> and |-(k - Δ), ↑> [or (|(k - Δ), ↓>) and |-(k + Δ), ↓>] states. In contrast, it was impossible to deduce the dispersion from the standing wave pattern at E ≥ E(x) because the surface electron cannot find its backscattered state with the same spin polarization.
我们研究了在 Bi/Ag(111)√3×√3 表面上，Si(111)衬底上的 10 层厚 Ag(111)薄膜中，Bi(p(x), p(y))轨道衍生的 j = 1/2 自旋分裂表面态中电子的量子干涉。在能量 (E)低于两个自旋分裂向下色散抛物线能带 (E(x))的交点处，清楚地观察到表面电子驻波。驻波图案的 E 依赖性揭示了由于 |(k + Δ), ↑> 和 |-(k - Δ), ↑> [或(|(k - Δ), ↓>) 和 |-(k + Δ), ↓>] 态之间的干涉，两个自旋分裂表面能带的平均色散。相比之下，由于表面电子无法找到具有相同自旋极化的反向散射状态，因此在 E≥E(x)处不可能从驻波图案推断出色散。
