Alkali-metal induced band structure deformation investigated by angle-resolved photoemission spectroscopy and first-principles calculations

作者：Ito S; Feng B; Arita M; Someya T; Chen W C; Takayama A; Iimori T; Namatame H; Taniguchi M; Cheng C M; Tang S J; Komori F; Matsuda I

来源：Physical Review B, 2018, 97(15): 155423.

DOI：10.1103/PhysRevB.97.155423

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.

• 出版日期2018-4-20
• 单位清华大学