Anisotropic superconducting gap in transuranium superconductor PuRhGa
; Ga NQR study on a single crystal
Sakai, Hironori
; Tokunaga, Yo
; Fujimoto, Tatsuya; Kambe, Shinsaku
; Walstedt, R. E.; Yasuoka, Hiroshi; Aoki, Dai*; Homma, Yoshiya*; Yamamoto, Etsuji
; Nakamura, Akio; Shiokawa, Yoshinobu; Nakajima, Kunihisa
; Arai, Yasuo; Matsuda, Tatsuma; Haga, Yoshinori
; Onuki, Yoshichika
Ga NMR/NQR studies have been performed on a single crystal of the transuranium superconductor PuRhGa
with
K. We have observed a
Ga NQR line at
29.15 MHz, and assigned it to the
Ga site using the NMR results. The
Ga NQR spin-lattice relaxation rate
shows no coherence peak just below
, but obeys
behavior below
. This result strongly suggests that PuRhGa
is an unconventional superconductor having an anisotropic superconducting gap. The gap amplitude 2
and the residual density of states
0.25 have been determined assuming a simple polar function of the form
=
, where
and
are angular parameters on the Fermi surface.