MgB2:: directional tunnelling two-band superconductivity

被引:15
作者
Iavarone, M
Karapetrov, G
Koshelev, A
Kwok, WK
Hinks, D
Crabtree, GW
Kang, WN
Chi, EM
Kim, HJ
Lee, SI
机构
[1] Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA
[2] Pohang Univ Sci & Technol, NCRICS, Pohang 790784, South Korea
[3] Pohang Univ Sci & Technol, Dept Phys, Pohang 790784, South Korea
关键词
D O I
10.1088/0953-2048/16/2/305
中图分类号
O59 [应用物理学];
学科分类号
摘要
We have studied the anisotropic superconductor MgB2 using a combination of scanning electron microscopy and scanning tunnelling spectroscopy. Tunnelling spectroscopy performed on thin films and pellets reveals two distinct energy gaps at Delta(1) = 2.3 meV and Delta(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 tunnelling directions with respect to the crystallographic orientation of the grain in a multiband system. Indeed when tunnelling 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 tunnelling 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].
引用
收藏
页码:156 / 161
页数:6
相关论文
共 24 条
[2]   Specific heat of Mg11B2:: Evidence for a second energy cap -: art. no. 047001 [J].
Bouquet, F ;
Fisher, RA ;
Phillips, NE ;
Hinks, DG ;
Jorgensen, JD .
PHYSICAL REVIEW LETTERS, 2001, 87 (04) :47001-1
[3]   Boron isotope effect in superconducting MgB2 [J].
Bud'ko, SL ;
Lapertot, G ;
Petrovic, C ;
Cunningham, CE ;
Anderson, N ;
Canfield, PC .
PHYSICAL REVIEW LETTERS, 2001, 86 (09) :1877-1880
[4]   Strange quark polarization of the nucleon: A parameter-independent prediction of the chiral potential model [J].
Chen, XB ;
Chen, XS ;
Wang, F .
PHYSICAL REVIEW LETTERS, 2001, 87 (01)
[5]  
CHOI JH, 2001, CONDMAT0111183
[6]   Vortex imaging in the π band of magnesium diboride -: art. no. 187003 [J].
Eskildsen, MR ;
Kugler, M ;
Tanaka, S ;
Jun, J ;
Kazakov, SM ;
Karpinski, J ;
Fischer, O .
PHYSICAL REVIEW LETTERS, 2002, 89 (18)
[7]   Strong coupling and double-gap density of states in superconducting MgB2 [J].
Giubileo, F ;
Roditchev, D ;
Sacks, W ;
Lamy, R ;
Klein, J .
EUROPHYSICS LETTERS, 2002, 58 (05) :764-770
[8]   Two-gap state density in MgB2:: A true bulk property or a proximity effect?: art. no. 177008 [J].
Giubileo, F ;
Roditchev, D ;
Sacks, W ;
Lamy, R ;
Thanh, DX ;
Klein, J ;
Miraglia, S ;
Fruchart, D ;
Marcus, J ;
Monod, P .
PHYSICAL REVIEW LETTERS, 2001, 87 (17) :177008-1
[9]  
GONNELLI RS, 2002, CONDMAT0208060
[10]   The complex nature of superconductivity in MgB2 as revealed by the reduced total isotope effect [J].
Hinks, DG ;
Claus, H ;
Jorgensen, JD .
NATURE, 2001, 411 (6836) :457-460