MgB{sub 2}: directional tunneling two-band superconductivity.

Conference · Sat Feb 01 04:00:00 EST 2003 · Supercond. Sci. Technol.

DOI:https://doi.org/10.1088/0953-2048/16/2/305· OSTI ID:947518

Iavarone, M; Karapetrov, G; Koshelev, A; Kwok, W K; Hinks, D; Crabtree, G W; Kang, W N; Choi, E -M; Kim, H J; Lee, S -I

We have studied the anisotropic superconductor MgB{sub 2} using a combination of scanning electron microscopy and scanning tunneling spectroscopy. Tunneling spectroscopy performed on thin films and pellets reveals two distinct energy gaps at {Delta}{sub 1} = 2.3 meV and {Delta}{sub 2} = 7.1 meV. On different crystallites within the polycrystalline sample different spectral weights of the partial densities of states (PDOS) were observed. They reflect different tunneling directions with respect to the crystallographic orientation of the grain in a multiband system. Indeed when tunneling in the c-axis films only one superconducting gap is observed, which is associated with the 3D band in this system. Temperature evolution of the tunneling spectra reveals that both gaps close simultaneously near the bulk critical temperature. Our experimental findings are consistent with the two-band superconductivity scenario in the presence of strong pair interaction between the two bands [1].

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 947518
• Report Number(s): ANL/MSD/CP-108327
• Conference Information: Journal Name: Supercond. Sci. Technol. Journal Issue: 2 ; Feb. 2003 Journal Volume: 16
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
ENERGY GAP
GRAIN ORIENTATION
MAGNESIUM BORIDES
SUPERCONDUCTIVITY