Quantum confinement in self-assembled two-dimensional nanoporous honeycomb networks at close-packed metal surfaces
Quantum confinement in self-assembled two-dimensional nanoporous honeycomb networks at close-packed metal surfaces
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DOI：
10.1063/1.4913244
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发表时间：
2015-03-14
影响因子：
4.4
通讯作者：
Barth, J. V.
中科院分区：
文献类型：
--
作者：
Kepcija, N.;Huang, T. -J.;Barth, J. V.
采用基于有限几何绿色函数和周期体系电子平面波展开的边界元方法，研究了二维电子气在超分子纳米多孔网络中的量子限制.“盒子中的粒子”图片进行了分析的情况下，与选定的对称性，模型先前报道的架构构建从有机和金属有机散射中心限制Ag（111）和Cu（111）的表面态电子。首先，通过分析一系列的情况下，系统定义的参数（散射几何形状，潜在的，和有效的拓宽），我们演示了散射过程如何影响的限制电子的属性。对于扫描隧道谱（STS）所报道的局域态密度的特征，我们分析了由于相邻量子点的耦合而导致的量子阱态的寿命展宽和分裂。对于每个系统，我们分析了本地电子密度分布，并将其与平面波展开框架内计算的相应的能带结构。然后，我们解决两个实验调查，其中在一种情况下，只有STS数据，在其他情况下，主要是角分辨光电子能谱（ARPES）数据的报告。在这两种情况下，实验结果可以成功地模拟。此外，缺失的信息可以得到补充，因为我们的方法允许相关的STS与ARPES的信息。几个观测结果的综合分析表明，由网络产生的散射电位主要来自吸附物引起的局部表面偶极势垒的变化。(C)2015年AIP Publishing LLC。
Quantum confinement of a two-dimensional electron gas by supramolecular nanoporous networks is investigated using the boundary elements method based on Green's functions for finite geometries and electron plane wave expansion for periodic systems. The "particle in a box" picture was analyzed for cases with selected symmetries that model previously reported architectures constructed from organic and metal-organic scattering centers confining surface state electrons of Ag(111) and Cu(111). First, by analyzing a series of cases with systematically defined parameters (scattering geometry, potentials, and effective broadening), we demonstrate how the scattering processes affect the properties of the confined electrons. For the features of the local density of states reported by scanning tunneling spectroscopy (STS), we disentangle the contributions of lifetime broadening and splitting of quantum well states due to coupling of neighboring quantum dots. For each system, we analyze the local electron density distribution and relate it to the corresponding band structure as calculated within the plane-wave expansion framework. Then, we address two experimental investigations, where in one case only STS data and in the other case mainly angle-resolved photoemission spectroscopy (ARPES) data were reported. In both cases, the experimental findings can be successfully simulated. Furthermore, the missing information can be complemented because our approach allows to correlate the information obtained by STS with that of ARPES. The combined analysis of several observations suggests that the scattering potentials created by the network originate primarily from the adsorbate-induced changes of the local surface dipole barrier. (C) 2015 AIP Publishing LLC.