Photoemission and tunneling as tests for fluctuating superconductivity above Tc in high-Tc superconductors

Abstract

We examine the hypothesis that fluctuating local superconducting order exists well above the critical temperature in high-Tc materials. This might explain anomalies in the magnetic susceptibility of some of these systems. It could also create a gap or pseudogap in the density of states, which could be measured by photoemission or tunneling experiments. We compute the density of states for a two-dimensional tight-binding model with such local order in the coherent-potential approximation. The order parameter is taken to have a spatially random phase and constant magnitude. We calculate this magnitude by a Ginzburg-Landau method. The conclusion is that the disorder smooths out the gap in the density of states unless the local order parameter is larger than the zero-temperature gap.

Source-reported materials — not catalogue approval

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