Fermi surface and superconducting gap of 2H-NbSe2 using low-temperature ultrahigh-resolution angle-resolved photoemission spectroscopy

Abstract

We have studied the Fermi surface (FS) and superconducting gap of 2H-NbSe2, using angle-resolved photoemission spectroscopy with an energy resolution of 2.2meV and an angle resolution of ±0.13°. We succeeded in distinguishing all FS sheets predicted from band calculations and found that the observed hexagonal Fermi surface nesting vector centered at the Γ point is larger than the CDW nesting vector reported from neutron diffraction measurements. Furthermore, a superconducting gap at one FS sheet is successfully observed.