Symmetry breaking and gap opening in two-dimensional hexagonal lattices
Symmetry breaking and gap opening in two-dimensional hexagonal lattices
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DOI：
10.1088/1367-2630/13/1/013026
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发表时间：
2011-01-01
影响因子：
3.3
通讯作者：
Ortega, J. E.
中科院分区：
文献类型：
--
作者：
Malterre, D.;Kierren, B.;Ortega, J. E.
带隙能量对波传播的抑制在许多技术领域发挥着核心作用，例如电子学（电子间隙）、纳米光子学（光间隙）和声学（声间隙）等。在这里，我们证明具有类自由电子带的金属表面可以通过周期性纳米结构变得半导体。我们结合扫描隧道光谱和角分辨光发射，准确确定了由三角形位错阵列图案化的Ag/Cu(111)贵金属界面的能量依赖的局部态密度和能带结构，证明了延伸到整个表面布里渊区的25 meV带隙的存在。我们证明了这种间隙是密排金属覆盖层对称性降低的普遍结果；特别是，我们表明间隙的打开是由于 K 点处的波矢组的对称性从 C-3v 降低到 C-3 造成的。
The inhibition in wave propagation at band gap energies plays a central role in many areas of technology such as electronics (electron gaps), nanophotonics (light gaps) and phononics (acoustic gaps), among others. Here we demonstrate that metal surfaces featuring free-electron-like bands may become semiconducting by periodic nanostructuration. We combine scanning tunneling spectroscopy and angle-resolved photoemisssion to accurately determine the energy-dependent local density of states and band structure of the Ag/Cu(111) noble metal interface patterned with an array of triangular dislocations, demonstrating the existence of a 25 meV band gap that extends over the entire surface Brillouin zone. We prove that this gap is a general consequence of symmetry reduction in close-packed metallic overlayers; in particular, we show that the gap opening is due to the symmetry lowering of the wave vector group at the K point from C-3v to C-3.