Two-band superconductivity in MgB2.
The study of the anisotropic superconductor MgB2 using a combination of scanning tunneling microscopy and spectroscopy reveals two distinct energy gaps at Delta(1)=2.3 meV and Delta(2)=7.1 meV at 4.2 K. Different spectral weights of the partial superconducting density of states are a reflection of different tunneling directions in this multiband system. Temperature evolution of the tunneling spectra follows the BCS scenario [Phys. Rev. Lett. 3, 552 (1959)]] with both gaps vanishing at the bulk T(c). The data confirm the importance of Fermi-surface sheet dependent superconductivity in MgB2 proposed in the multigap model by Liu et al. [Phys. Rev. Lett. 87, 087005 (2001)]].
Iavarone
M
M
Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Karapetrov
G
G
Koshelev
A E
AE
Kwok
W K
WK
Crabtree
G W
GW
Hinks
D G
DG
Kang
W N
WN
Choi
Eun-Mi
EM
Kim
Hyun Jung
HJ
Kim
Hyeong-Jin
HJ
Lee
S I
SI