Observation of thermally activated glassiness and memory dip in a-NbSi insulating thin films
1 Institut Néel, CNRS and Université Joseph Fourier - BP 166, 38042 Grenoble, France
2 CSNSM, Université Paris-Sud - Orsay, F-91405, France
Received: 18 April 2014
Accepted: 4 June 2014
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.
PACS: 72.20.Ee – Mobility edges; hopping transport / 72.80.Ng – Disordered solids / 73.40.Qv – Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
© EPLA, 2014