| Summary: | We report on non equilibrium field effect in insulating amorphous NbSi thin
films having different Nb contents and thicknesses. The hallmark of an electron
glass, namely the logarithmic growth of a memory dip in conductance versus gate
voltage curves, is observed in all the films after a cooling from room
temperature to 4.2 K. A very rich phenomenology is demonstrated. While the
memory dip width is found to strongly vary with the film parameters, as was
also observed in amorphous indium oxide films, screening lengths and
temperature dependence of the dynamics are closer to what is observed in
granular Al films. Our results demonstrate that the differentiation between
continuous and discontinuous systems is not relevant to understand the
discrepancies reported between various systems in the electron glass features.
We suggest instead that they are not of fundamental nature and stem from
differences in the protocols used and in the electrical inhomogeneity length
scales within each material.
|
|---|