Spin-resolved band structure of a densely packed Pb monolayer on Si(111)
Spin-resolved band structure of a densely packed Pb monolayer on Si(111)
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DOI：
10.1103/physrevb.96.035432
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发表时间：
2017-07-24
影响因子：
3.7
通讯作者：
Tegenkamp, C.
中科院分区：
文献类型：
--
作者：
Brand, C.;Muff, S.;Tegenkamp, C.
Pb在Si（111）上的单层结构最近引起了相当大的兴趣，因为在这些真正的二维（2D）结构中发现了超导性。在这项研究中，我们分析了所谓的条纹无公度Pb相的电子表面能带结构的4/3 ML覆盖的自旋分辨光电子能谱。我们的结果与Ren等人的密度泛函理论计算完全一致[Phys. Rev. B 94，075436（2016）]。我们观察到一个完全占据和自旋极化的表面带的局部塞曼型分裂的带（K）在酒吧根3点。这种密集堆积的Pb结构的生长导致形成不平衡的旋转畴，这触发了费米能周围的表面态的C-3v对称性禁戒自旋分量的检测。此外，该相的金属表面态的费米面是Rashba自旋分裂的，并显示出明显的翘曲。然而，2D嵌套矢量与原子结构不相称，因此保持该系统相当不受电荷密度波形成的影响，并可能实现超导行为。
Monolayer structures of Pb on Si(111) attracted recently considerable interest as superconductivity was found in these truly two-dimensional (2D) structures. In this study, we analyzed the electronic surface band structure of the so-called striped incommensurate Pb phase with 4/3 ML coverage by means of spin-resolved photoemission spectroscopy. Our results fully agree with density functional theory calculations done by Ren et al. [Phys. Rev. B 94, 075436 (2016)]. We observe a local Zeeman-type splitting of a fully occupied and spin-polarized surface band at the band at the (K) over bar root 3 points. The growth of this densely packed Pb structure results in the formation of imbalanced rotational domains, which triggered the detection of C-3v symmetry forbidden spin components for surface states around the Fermi energy. Moreover, the Fermi surface of the metallic surface state of this phase is Rashba spin split and revealed a pronounced warping. However, the 2D nesting vectors are incommensurate with the atomic structure, thus keeping this system rather immune against charge density wave formation and possibly enabling a superconducting behavior.