engleski

Superconducting percolation in the cuprates

The superconducting emergence regime above the macroscopic Tc provides crucial information on both the normal and superconducting states and has long been the subject of controversy in the cuprate superconductors. We present a systematic investigation of the emergence of superconductivity in cuprates using nonlinear conductivity – a probe which eliminates background subtraction problems because the signal vanishes in the normal state. Through experiments on several cuprate families and throughout the phase diagram, we show that the regime above Tc is universally incompatible with the frequently evoked Ginzburg-Landau theory. Instead, it is dominated by disorder, irrespective of cuprate family or doping. A simple superconducting percolation model describes our results very well, allowing us to explain several conflicting results of previous investigations and create an overarching picture of charge carrier behavior in the cuprates, with disorder playing a crucial role.

superconductivity emergence; cuprates; nonlinear conductivity; high-Tc

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