Department of Physics, Chemistry, and Biology, Linköping University, Sweden.
Phys Rev Lett. 2012 Aug 3;109(5):057601. doi: 10.1103/PhysRevLett.109.057601. Epub 2012 Aug 1.
The existence of a highly ordered, two-dimensional, Sn/Ag alloy on Si(111) is reported in this study. We present detailed atomic and electronic structures of the one atomic layer thick alloy, exhibiting a 2 × 2 periodicity. The electronic structure is metallic due to a free-electron-like surface band dispersing across the Fermi level. By electron doping, the electronic structure can be converted into a semiconducting state. A rotated Sn trimer constitutes the key structural element that could be identified by a detailed analysis of constant energy contours derived from the free-electron-like band.
本研究报道了在 Si(111)上存在高度有序的二维 Sn/Ag 合金。我们呈现了这种单层厚合金的详细原子和电子结构，具有 2×2 的周期性。由于表面能带在费米能级附近自由电子样地分散，所以电子结构是金属性的。通过电子掺杂，可以将电子结构转换为半导体状态。一个旋转的 Sn 三聚体构成了关键的结构元素，可以通过对自由电子样能带导出的等能轮廓的详细分析来识别。
