Evidencing the need for high spatial resolution in angle-resolved photoemission experiments

Abstract

Angle-resolved photoemission spectroscopy (ARPES) provides direct access to the electronic band structure of materials. Very recently, the spatial resolution of ARPES setups has dramatically increased, with a spot size at the sample shrinking from 50$\ifmmode\times\else\texttimes\fi{}$50 $\ensuremath{\mu}$m${}^{2}$, typical of most synchrotron-based setups, down to 100$\ifmmode\times\else\texttimes\fi{}$100 nm${}^{2}$ or less. In this work, the authors demonstrate the impact of increased spatial resolution by evidencing faint spatial inhomogeneity in the ARPES signal of a graphene sample that would go undetected in ARPES setups possessing lower spatial resolution.