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Theory of the sign of multi-probe conductances for normal and superconducting materials

Research output: Contribution to journalJournal article


<mark>Journal publication date</mark>28/11/1994
<mark>Journal</mark>Journal of Physics: Condensed Matter
Issue number48
Number of pages12
Pages (from-to)10475-10486
<mark>Original language</mark>English


We examine equivalent forms of the current-voltage relationship applicable to mesoscopic superconductors and use one of these to derive general conditions for the sign of the conductance in a four-probe measurement. For disordered systems, with well separated voltage probes, where the normal-state conductance is positive, we predict that the sign of the longitudinal four-probe conductance of superconducting wires can be reversed by varying an applied magnetic field, and that at certain critical values of the field, the conductance passes through a singularity.