Band structure and Fermi surface of URu_2Si_2 studied by soft x-ray angle-resolved photoemission spectroscopy

摘要

We have performed angle-resolved photoelectron spectroscopy experiments in the soft x-ray region in order to clarify the band structure and Fermi surfaces (FSs) of URu_2Si_2. In the vicinity of the Fermi level, U 5f-derived quasiparticle bands were clearly observed. They form a small and a large hole FS centered at the Z point and a large electron FS centered at the Γ point. The overall band structure as well as the FSs are explained by a band structure calculation treating all U 5/ electrons as being itinerant. The observed FSs have nesting vectors which give a possible explanation for the spin fluctuations observed by inelastic neutron scattering measurements.