Improvement of display-type spherical mirror analyzer for real space mapping of electronic and atomic structures

We have improved a display-type spherical mirror analyzer (DIANA) at Ritsumeikan University SR Center BL-7 for in situ real space mapping of electronic and atomic structures that uses a focused electron beam and a linearly polarized synchrotron radiation (SR). The outer sphere was fully optimized. Compared to the previous analyzer, the energy resolution (ΔE/E) has been improved from 1% to 0.09±0.02%. A newly designed electron gun for measurement of atomic structures was installed inside the analyzer. Thus the measurement of electronic and atomic structures at the same sample position became possible. Here we report on the improvements of the new DIANA and the results of the first in situ measurement of real space mapping of the valence band and scanning Auger electron microscopy (SAM) of a multiple domain Kish graphite. The crystal orientations of each domain were determined from the electronic structures.