Alkali-metal induced band structure deformation investigated by angle-resolved photoemission spectroscopy and first-principles calculations
Alkali-metal induced band structure deformation investigated by angle-resolved photoemission spectroscopy and first-principles calculations
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DOI：
10.1103/physrevb.97.155423
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发表时间：
2018-04-20
影响因子：
3.7
通讯作者：
Matsuda, I.
中科院分区：
文献类型：
--
作者：
Ito, S.;Feng, B.;Matsuda, I.
碱金属在材料表面的吸附被广泛用于原位表面电子掺杂，特别是用于通过角分辨光电子能谱（ARPES）观察未占据的能带结构。然而，碱金属原子对所产生的能带结构的影响尚未得到充分的研究，由于在实验和计算的困难。在这里，我们结合联合收割机的ARPES测量铯吸附铋薄膜的电子电荷密度的第一性原理计算，并证明了一个简单的方法来评估碱金属引起的带变形。我们发现，变形的铋表面带是直接相关的垂直电荷密度分布在每个电子状态的铋。相比之下，在量化的体带的变化是很好地描述了一个传统的刚性带移图片。我们从整体上讨论了这两个方面的能带变形，考虑空间分布的电子态和铯-铋杂化，并提供了一个处方应用碱金属吸附到广泛的材料。
Alkali-metal adsorption on the surface of materials is widely used for in situ surface electron doping, particularly for observing unoccupied band structures by angle-resolved photoemission spectroscopy (ARPES). However, the effects of alkali-metal atoms on the resulting band structures have yet to be fully investigated, owing to difficulties in both experiments and calculations. Here, we combine ARPES measurements on cesium-adsorbed ultrathin bismuth films with first-principles calculations of the electronic charge densities and demonstrate a simple method to evaluate alkali-metal induced band deformation. We reveal that deformation of bismuth surface bands is directly correlated with vertical charge-density profiles at each electronic state of bismuth. In contrast, a change in the quantized bulk bands is well described by a conventional rigid-band-shift picture. We discuss these two aspects of the band deformation holistically, considering spatial distributions of the electronic states and cesium-bismuth hybridization, and provide a prescription for applying alkali-metal adsorption to a wide range of materials.