Spectromicroscopic Analysis of Surface and Bulk Band Structure at a Disordered Topological Insulator Surface

The technique of angle resolved photoemission spectroscopy (ARPES) is widely applied to measure electronic band structures and has become central to our understanding of quantum material electronic structures over the last few decades. Recent improvements in coherent VUV light sources have driven rapid developments in the focused beam spot for ARPES, down to the d<10um diameter scale with little sacrifice, and the d~100nm scale with reduced flux. For this talk I will present ARPES spectromiscroscopy data which was used to map the surface band structure of a beam-sensitive topological insulator sample (disorder-enriched Bi2Se3). New data analysis methods are developed to obtain quantitative electronic structure information in spite of the flux sensitivity of the surface, revealing a complex structural environment in which fluctuations in the surface and bulk state energetics are found to be mostly decoupled.