Saveskul NA, Titova NA, Baeva EM, Semenov AV, Lubenchenko AV, Saha S, et al. Superconductivity behavior in epitaxial TiN films points to surface magnetic disorder. Phys Rev Applied. 2019;12(5):054001.
Abstract: We analyze the evolution of the normal and superconducting properties of epitaxial TiN films, characterized by high Ioffe-Regel parameter values, as a function of the film thickness. As the film thickness decreases, we observe an increase of the residual resistivity, that becomes dominated by diffusive surface scattering for d≤20nm. At the same time, a substantial thickness-dependent reduction of the superconducting critical temperature is observed compared to the bulk TiN value. In such high-quality material films, this effect can be explained by a weak magnetic disorder residing in the surface layer with a characteristic magnetic defect density of approximately 1012cm−2. Our results suggest that surface magnetic disorder is generally present in oxidized TiN films.
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Santhanam P, Wind S, Prober DE. Localization, superconducting fluctuations, and superconductivity in thin films and narrow wires of aluminum. Phys Rev B. 1987;35(7):3188–206.
Abstract: We report a comprehensive set of experiments on wide and narrow thin-film strips of aluminum which test the predictions of recent localization theory. The experiments on wide films in the two-dimensional regime confirm the theoretical predictions and also yield insight into inelastic mechanisms and spin-orbit scattering rates. Our extension of the existing theory for one-dimensional systems to include spin-orbit scattering and Maki-Thompson superconducting fluctuations is verified by the experiments. We find clear evidence for one-dimensional localization, with inferred inelastic rates identical to those in two-dimensional films. The prediction of the localization theory for a dimensional crossover from two-dimensional to one-dimensional behavior is also confirmed. We have reanalyzed the results of some previous experiments on thin films and narrow wires in light of these results.
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Romijn J, Klapwijk TM, Renne MJ, Mooij JE. Critical pair-breaking current in superconducting aluminum strips far below Tc. Phys Rev B. 1982;26(7):3648–55.
Abstract: Critical currents of narrow, thin aluminum strips have been measured as a function of temperature. For the smallest samples uniformity of the current density is obtained over a large temperature range. Hence the intrinsic limit on the currentcarrying capacity of the superconductor was measured outside the Ginzburg-Landau -regime. The experimental values are compared with recent theoretical predictions by Kupriyanov and Lukichev. An approximate method of solving their equations is given, the results of which agree with the exact solution to within 1%. Experimental data are in excellent agreement with theoretical predictions. The absolute values agree if one assumes a Ïl value of 4×10–16 Ωm2 with vF=1.3×106 m/s. This value for Ïl is the same as that found from measurements of the anomalous skin effect but differs from values extracted from size-effect-limited resistivity.
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Ptitsina NG, Chulkova GM, Il’in KS, Sergeev AV, Pochinkov FS, Gershenzon EM, et al. Electron-phonon interaction in disordered metal films: The resistivity and electron dephasing rate. Phys Rev B. 1997;56(16):10089–96.
Abstract: The temperature dependence of the resistance of films of Al, Be, and NbC with small values of the electron mean free path l=1.5–10nm has been measured at 4.2–300 K. The resistance of all the films contains a T2 contribution that is proportional to the residual resistance; this contribution has been attributed to the interference between the elastic electron scattering and the electron-phonon scattering. Fitting the data to the theory of the electron-phonon-impurity interference (M. Yu. Reiser and A. V. Sergeev, Zh. Eksp. Teor. Fiz. 92, 224 (1987) [Sov. Phys. JETP 65, 1291 (1987)]), we obtain constants of interaction of the electrons with transverse phonons, and estimate the contribution of this interaction to the electron dephasing rate in thin films of Au, Al, Be, Nb, and NbC. Our estimates are in a good agreement with the experimental data on the inelastic electron-phonon scattering in these films. This indicates that the interaction of electrons with transverse phonons controls the electron-phonon relaxation rate in thin-metal films over a broad temperature range.
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Ptitsina N. G., Chulkova G. M., Il'in K. S., Sergeev A. V., Pochinkov F. S., Gershenzon E. M. Superconductivity has been found in a number of new compounds between the non-superconducting transition elements and nonmetals such as Si, Ge, and Te. These findings have suggested possible criteria for superconductivity in both elements and compounds. Phys Rev B. 1997;56(16).
Abstract: The temperature dependence of the resistance of films of Al, Be, and NbC with small values of the electron mean free path L=1.5– 10 nm has been measured at 4.2–300 K. The resistance of all the films contains a T^2 contribution that is proportional to the residual resistance; this contribution has been attributed to the interference between the elastic electron scattering and the electron-phonon scattering. Fitting the data to the theory of the electron-phonon-impurity interference „M. Yu. Reiser and A. V. Sergeev, Zh. Eksp. Teor. Fiz. 92, 224 ~1987! @Sov. Phys. JETP 65, 1291 ~1987!#…, we obtain constants of nteraction of the electrons with transverse phonons, and estimate the contribution of this interaction to the electron dephasing rate in thin films of Au, Al, Be, Nb, and NbC. Our estimates are in a good agreement with the experimental data on the inelastic electronphonon scattering in these films. This indicates that the interaction of electrons with transverse phonons controls the electron-phonon relaxation rate in thin-metal films over a broad temperature range.
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