Observation of thermally activated glassiness and memory dip in a-NbSi insulating thin films

Julien Delahaye (1) , Thierry Grenet (1) , C. Marrache-Kikuchi (2) , L. Bergé (3) , A. A. Drillien (4)

1 NEEL - MagSup - Magnétisme et Supraconductivité
2 CSNSM PS2
3 CSNSM INSTRU
4 CSNSM - Centre de Sciences Nucléaires et de Sciences de la Matière

We present electrical conductance measurements on amorphous NbSi insulating thin films. These films display out-of equilibrium electronic features that are markedly different from what has been reported so far in disordered insulators. Like in the most studied systems (indium oxide and granular Al films), a slow relaxation of the conductance is observed after a quench to liquid helium temperature which gives rise to the growth of a memory dip in MOSFET devices. But unlike in these systems, this memory dip and the related conductance relaxations are still visible up to room temperature, with clear signatures of a temperature dependent dynamics.

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

Julien Delahaye, Thierry Grenet, C. Marrache-Kikuchi, L. Bergé, A. A. Drillien. Observation of thermally activated glassiness and memory dip in a-NbSi insulating thin films. EPL - Europhysics Letters, 2014, 106 (6), pp.67006. ⟨10.1209/0295-5075/106/67006⟩. ⟨hal-01015916⟩