Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche , Strada Statale 14 km 163.5, I-34149 Trieste, Italy.
Elettra Sincrotrone Trieste , Strada Statale 14 km 163.5, I-34149 Trieste, Italy.
ACS Nano. 2017 Jan 24;11(1):975-982. doi: 10.1021/acsnano.6b07593. Epub 2017 Jan 11.
Silicene, a honeycomb lattice of silicon, presents a particular case of allotropism on Ag(111). Silicene forms multiple structures with alike in-plane geometry but different out-of-plane atomic buckling and registry to the substrate. Angle-resolved photoemission and first-principles calculations show that these silicene structures, with (4×4), (√13×√13)R13.9°, and (2√3×2√3)R30° lattice periodicity, display similar electronic bands despite the structural differences. In all cases the interaction with the substrate modifies the electronic states, which significantly differ from those of free-standing silicene. Complex photoemission patterns arise from surface umklapp processes, varying according to the periodicity of the silicene allotropes.
硅烯，一种硅的蜂窝状晶格，在 Ag(111) 上呈现出一种特殊的同素异形现象。硅烯形成了多种具有相似面内几何形状但不同的面外原子翘曲和与衬底的配位数的结构。角分辨光电子能谱和第一性原理计算表明，尽管存在结构差异，但这些具有 (4×4)、(√13×√13)R13.9° 和 (2√3×2√3)R30° 晶格周期性的硅烯结构，具有相似的电子能带。在所有情况下，与衬底的相互作用都会改变电子态，这与自由-standing 硅烯的电子态有很大的不同。复杂的光电子发射模式源于表面 umklapp 过程，其变化取决于硅烯同素异形的周期性。
