scholarly journals A NEW METHOD FOR DETERMINING THE ENERGY GAP OF A SUPERCONDUCTOR USING THE MAXIMUM IN DIFFERENTIAL CONDUCTANCE OF ELECTRON TUNNELING SPECTRUM

1986 ◽  
Vol 35 (2) ◽  
pp. 266
Author(s):  
LI HONG-CHENG ◽  
WANG RUI-LAN ◽  
WANG PING-SHU ◽  
GUAN WEI-YEN
Keyword(s):  
Energy Gap ◽  
Electron Tunneling ◽  
New Method ◽  
Differential Conductance ◽  
Tunneling Spectrum

A new method of superconducting energy gap spectroscopy

1998 ◽  
Vol 297 (3-4) ◽  
pp. 232-238
Author(s):  
G.A. Gogadze ◽  
V.M. Svistunov ◽  
R. Aoki ◽  
H. Murakami ◽  
M. Shirai
Keyword(s):  
Energy Gap ◽  
New Method ◽  
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.

scholarly journals A METHOD OF TEMPERATURE CORRECTION FOR ELECTRON TUNNELING SPECTRUM

1986 ◽  
Vol 35 (3) ◽  
pp. 393
Author(s):  
LI HONG-CHENG ◽  
WANG RUI-LAN ◽  
WANG PING-SHU ◽  
GUAN WEI-YAN
Keyword(s):  
Electron Tunneling ◽  
Temperature Correction ◽  
Tunneling Spectrum

Molecular Degradation in the Electron Microscope: A Tunneling Spectroscopy Study

1975 ◽  
Vol 33 ◽  
pp. 244-245
Author(s):  
M. Parikh ◽  
P. K. Hansma
Keyword(s):  
Electron Microscope ◽  
Electron Tunneling ◽  
Physical Structure ◽  
Tunneling Spectroscopy ◽  
Inelastic Electron ◽  
Tunneling Spectrum ◽  
Inelastic Electron Tunneling Spectroscopy ◽  
Loss Analysis ◽  
Inelastic Electron Tunneling ◽  
Electron Tunneling Spectroscopy

Molecular degradation in the electron microscope has been studied by energy loss spectroscopy, mass loss analysis and other techniques; none of these, however, have provided explicit information about the changes in the physical structure of the molecules. Here we present results from the use of inelastic electron tunneling spectroscopy as a probe in the study of degradation of molecular specimens in an electron microscope. The technique involves including the molecules of interest in a metal-insulatormetal junction and then monitoring the junctions current-voltage (I-V) characteristic. Explicitly, the measurement of d2I/dV2 vs. V provides a spectrum of vibrational frequencies (related to IR and Raman active modes) of the molecule; thus information about molecular bonds and physical configuration can be obtained. Upon electron irradiation, changes in the molecular structure are visible as changes in the heights and positions of the peaks in the tunneling spectrum.

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