General equations for the dynamic behavior of dirty superconductors in the Ginzburg-Landau regime T
c-T ≪ T
care derived from microscopic theory. In the immediate vicinity of T
ca local equilibrium approximation leads to a simple generalized time-dependent Ginzburg-Landau equation. The oscillatory phase-slip solutions presented previously are discussed in greater detail.

Nonequilibrium theory of dirty, current-carrying superconductors: phase-slip oscillators in narrow filaments near T c

Bulk rhombohedral Bi at ambient pressure is a well-known semimetal, and its transition to a superconductor has not been observed, at least down to 50 mK. We report that, unlike bulk rhombohedral Bi, granular Bi nanowires with well-defined rhombohedral grains of approximately 10 nm diameter, fabricated by electrochemically depositing Bi into porous polycarbonate membranes at ambient pressure, are superconducting with two transition temperatures, Tc, of 7.2 and 8.3 K. These Tc values coincide with Tc values of the high-pressure phases Bi-III and Bi-V, respectively. Analysis of our structural and transport data indicates that the superconductivity in granular Bi nanowires probably arises from grain boundary areas where there are structural reconstructions between the grains showing a preferred orientation within a small angular distribution.

Observation of superconductivity in granular bi nanowires fabricated by electrodeposition.

We have investigated the effects of a magnetic field H on nonequilibrium quasiparticle relaxation processes in superconductors by analyzing the I–V characteristics of long tin microbridges in a parallel field near T
c
(H). Following Skocpol, Beasley, and Tinkham, we take the differential resistance of a given phase-slip center (PSC) to be approximately equal to the normal resistance R
n of a nonequilibrium region of the bridge with length 2(DΤR)1/2, where D is the quasiparticle diffusion constant andΤ
 R
 is the transverse mode (branch imbalance) relaxation time. The magnitude and the temperature and field dependence ofΤ
 R
 as inferred from our data agree well with those of the transverse mode relaxation time in the presence of pair-breaking, derived by Schmid and Schon. The longitudinal mode disequilibrium is interpreted in terms of local heating proportional to IV, and the resulting distortions in the I–V characteristics are corrected. Most of our samples contain a deliberate weak spot with a depressed critical current I
c, which isolates a single PSC and lowers the heat dissipation(~I
c
2Rn).

Magnetic field dependence of relaxation times in nonequilibrium superconductors

Theoretical step structures for ideal homogeneous filaments based on the interactions implicit in the simple phase-slip-center model of Skocpol, Beasley, and Tinkham are displayed explicitly.

R. Tidecks

Papers

Investigation of the current induced phase transition of superconducting tin whiskers with several potential probes

Mutual influence of voltage steps in the V I characteristics of current-carrying superconducting tin whiskers

The influence of the electron mean free path on phase-slip centers in indium whiskers

Current-induced superconducting — normal transition of zinc whiskers near the critical temperature