Electronic structure of UN; Angle resolved photoelectron spectroscopy study

Fujimori, Shinichi   ; Okochi, Takuo*; Okane, Tetsuo  ; Saito, Yuji  ; Fujimori, Atsushi; Yamagami, Hiroshi; Aoki, Dai*; Yamamoto, Etsuji  ; Onuki, Yoshichika; Haga, Yoshinori   

Uranium nitride (UN) is a type I antiferromagnet with Nel temperature =53 K. Since U-U distance in this compound (3.46 ) is close to the Hill limit (3.4 ), nature of U 5 electrons has been debated so far between localized and itinerant states. Recently, it has been suggested that the U 5 electrons in this compound have dual (itinerant and localized) characters. We have studied Fermi surface and band structure of single crystal UN by angle resolved photoelectron spectroscopy (ARPES) to understand the nature of U 5 states. In contrast to the previous ARPES results, quasi-particle bands originated from U 5states were clearly observed in the present ARPES spectra. The obtained Fermi surface as well as band structure were well explained by the band structure calculation treating all U 5 electrons as being itinerant. We have found that U 5 electrons in this compound are very itinerant, and the antifferomagnetism in this compound is an itinerant origin.