Manifestation of ageing in the low temperature conductance of disordered insulators
Institut Néel, CNRS & Université Joseph Fourier, BP 166, 38042 Grenoble Cedex 9, France
Corresponding author: a email@example.com
Revised: 23 April 2010
Published online: 17 June 2010
We are interested in the out of equilibrium phenomena observed in the electrical conductance of disordered insulators at low temperature, which may be signatures of the electron coulomb glass state. The present work is devoted to the occurrence of ageing, a benchmark phenomenon for the glassy state. It is the fact that the dynamical properties of a glass depend on its age, i.e. on the time elapsed since it was quench-cooled. We first critically analyse previous studies on disordered insulators and question their interpretation in terms of ageing. We then present new measurements on insulating granular aluminium thin films which demonstrate that the dynamics is indeed age dependent. We also show that the results of different relaxation protocols are related by a superposition principle. The implications of our findings for the mechanism of the conductance slow relaxations are then discussed.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2010