Observation of a superconducting gap in boron-doped diamond by laser-excited photoemission spectroscopy.
We investigate the temperature (T)-dependent low-energy electronic structure of a boron-doped diamond thin film using ultrahigh resolution laser-excited photoemission spectroscopy. We observe a clear shift of the leading edge below T=11 K, indicative of a superconducting gap opening (Delta approximately 0.78 meV at T=4.5 K). The gap feature is significantly broad and a well-defined quasiparticle peak is lacking even at the lowest temperature of measurement (=4.5 K). We discuss our results in terms of disorder effects on the normal state transport and superconductivity in this system.
Ishizaka
K
K
Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
Eguchi
R
R
Tsuda
S
S
Yokoya
T
T
Chainani
A
A
Kiss
T
T
Shimojima
T
T
Togashi
T
T
Watanabe
S
S
Chen
C-T
CT
Zhang
C Q
CQ
Takano
Y
Y
Nagao
M
M
Sakaguchi
I
I
Takenouchi
T
T
Kawarada
H
H
Shin
S
S