Superconducting Energy Gap of Thorium Determined by Electron Tunneling

1972 ◽  
Vol 5 (11) ◽  
pp. 4364-4367 ◽  
Author(s):  
B. A. Haskell ◽  
W. J. Keeler ◽  
D. K. Finnemore
Keyword(s):  
Energy Gap ◽  
Electron Tunneling ◽  
Superconducting Energy Gap

Electron Tunneling in High Tc Superconductors

MRS Bulletin ◽  
1990 ◽  
Vol 15 (6) ◽  
pp. 44-49 ◽  
Author(s):  
J.M. Valles ◽  
R.C. Dynes
Keyword(s):  
Energy Gap ◽  
Electron Tunneling ◽  
Quantitative Description ◽  
Bcs Theory ◽  
Phonon Interaction ◽  
Microscopic Mechanism ◽  
Electron Phonon Interaction ◽  
Current Voltage ◽  
Superconducting Energy Gap ◽  
Electron Phonon Coupling

Electron tunneling measurements have proven enormously valuable in studies of conventional superconductors. Very early measurements confirmed, in an especially convincing way, the existence of the superconducting energy gap, and more detailed studies demonstrated the spectral form of the gap and its temperature dependence. These measurements were instrumental in confirming in some detail the predictions of the Bardeen, Cooper, Schrieffer (BCS) theory of superconductivity in simple metals. For example, it was shown very clearly that the ratio of the energy gap (2Δ) and critical temperature Tc was close to the BCS value (2Δ/kTc = 3.5). As the sophistication of the technique improved, deviations from this BCS weak coupling limit became apparent (2Δ/kTc was measured to be >4 in materials like Pb, for example), and subtle structure in the current-voltage characteristics of tunnel junctions unearthed a signature of the electron-phonon interaction—the microscopic mechanism responsible for superconductivity in these traditional materials. Through a quantitative analysis of this structure, people were able to extract a function α2(ω)F(ω), which is the phonon density of states F(ω) modulated by the electron-phonon coupling function α2(ω). This function gave a quantitative description of the electron-phonon interaction and confirmed beyond a doubt that the electron-phonon interaction was responsible for superconductivity.

ELECTRON TUNNELING MEASUREMENTS OF ENERGY GAP IN SUPERCONDUCTORS YBaCuO, LaSrCuO AND BPBO

1987 ◽  
Vol 01 (02) ◽  
pp. 555-559 ◽  
Author(s):  
Hongjie TAO ◽  
Yingfei CHEN ◽  
Li LU ◽  
Qiansheng YANG ◽  
Bairu ZHAO ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Strong Coupling ◽  
Perovskite Structure ◽  
Energy Gap ◽  
Electron Tunneling ◽  
Point Contact ◽  
Tunneling Conductance ◽  
Temperature Ratio ◽  
Superconducting Energy Gap

We have carried out superconducting energy gap measurements for polycrystalline perovskite-structure superconductors YBaCuO, LaSrCuO and BPBO with point contact tunneling. The tunneling conductance curves for YBaCuO, LaSrCuO and BPBO show the energy gap to transition temperature ratio 2Δ/kTc =4.7, 7.8 and 5.05 respectively, which is consistant with the strong-coupling superconductivity.

Single electron tunneling and superconducting energy gap in YBa2Cu3O7−δ and TlBa2Ca2Cu3O9+-δ films

1997 ◽  
Vol 282-287 ◽  
pp. 1531-1532 ◽  
Author(s):  
R.T. Kao ◽  
S.J. Wang ◽  
S.P. Chen ◽  
J.Y. Juang ◽  
K.H. Wu ◽  
...  
Keyword(s):  
Energy Gap ◽  
Electron Tunneling ◽  
Single Electron ◽  
Superconducting Energy Gap ◽  
Single Electron Tunneling
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