Soft X-Ray Arpes For Three-Dimensional Crystals In The Micrometre Region

An endstation dedicated to angle-resolved photoemission spectroscopy (ARPES) using a soft X-ray microbeam has been developed at the beamline BL25SU of SPring-8. To obtain a high photoemission intensity, this endstation is optimized for measurements under the condition of grazing beam incidence to a sample surface, where the glancing angle is 5 degrees or smaller. A Wolter mirror is used for focusing the soft X-rays. Even at the glancing angle of 5 degrees, the smallest beam spot still having a sufficient photon flux for ARPES is almost round on the sample surface and the FWHM diameter is similar to 5 mu m. There is no need to change the sample orientation for performing k(x) - k(y) mapping by virtue of the electron lens with a deflector of the photoelectron analyzer, which makes it possible to keep the irradiation area unchanged. A partially cleaved surface area as small as similar to 20 mu m was made on an Si(111) wafer and ARPES measurements were performed. The results are presented.