Using High Energy Angle Resolved Photoelectron Spectroscopy to Reveal the Charge Density in Solids

The charge density in solids is a fundamental parameter. Here we demonstrate that the charge density can be determined by the use of angle resolved photoelectron spectroscopy. The method, which involves a Fourier-like transform from momentum space to real space, is demonstrated by utilizing soft x-ray angle resolved photoelectron spectroscopy to sample the complete three-dimensional Brillouin zone of copper. It is also shown that this can be done in an energy resolved way as to extract the charge density contribution from states of a particular energy.