Anomalous field effect and glassy behaviour in granular aluminium thin films: electron glass?

Thierry Grenet (1) , Julien Delahaye (1) , Maher Sabra , Frédéric Gay (2)

1 NEEL - MagSup - Magnétisme et Supraconductivité
2 NEEL - AUTOCARAC - Automatisation & caractérisation

We present a study of non-equilibrium phenomena observed in the electrical conductance of insulating granular aluminium thin films. An anomalous field effect and its slow relaxation are studied in some detail. The phenomenology is very similar to the one already observed in indium oxide. The origin of the phenomena is discussed. In granular systems, the present experiments can naturally be interpreted along two different lines. One relies on a slow polarisation in the dielectric surrounding the metallic islands. The other one relies on a purely electronic mechanism: the formation of an electron Coulomb glass in the granular metal. More selective experiments and/or quantitative predictions about the Coulomb glass properties are still needed to definitely distinguish between the two scenarii.

Mots clés: time-dependent properties; relaxation; disordered solids; Coulomb blockade; single electron tunnelling

Domaines: Systèmes désordonnés et réseaux de neurones [cond-mat.dis-nn]

Thierry Grenet, Julien Delahaye, Maher Sabra, Frédéric Gay. Anomalous field effect and glassy behaviour in granular aluminium thin films: electron glass?. The European Physical Journal B: Condensed Matter and Complex Systems, 2007, 56 (3), pp.183. ⟨10.1140/epjb/e2007-00109-4⟩. ⟨hal-00126128v2⟩