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

Abstract

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.

arXiv comment8 pages, 7 figures

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Cited by in corpus (4)

• Theory of spin and orbital charge conversion at the surface states of Bi_{1-x}Sb_x topological insulator
• Effect of the sample work function on alkali metal dosing induced electronic structure change
• Switching of magnetism via modifying phase shift of quantum-well states by tailoring the interface electronic structure
• Angle-resolved photoelectron spectroscopy in a low energy electron microscope