Related papers: Anomalous field effect and glassy behaviour in gra…
Conductivity and field effect measurements in thin insulating Al granular films are reported. The occurrence of a symmetrical field effect and of very slow conductance relaxations is demonstrated. They are identical to the electron glassy…
We present new results obtained by field effect measurements on insulating granular Al thin films. First, reproducible and stable conductance fluctuations are seen in micron size samples as a function of gate voltage. The anomalous field…
We perform electrical field effect measurements at 4 K on insulating granular aluminium thin films. When the samples size is reduced below 100 micrometers, reproducible and stable conductance fluctuations are seen as a function of the gate…
It is shown that the conductance relaxations observed in electrical field effect measurements on granular Al films are the sum of two contributions. One is sensitive to gate voltage changes and gives the already reported anomalous…
We present a new set of electrical field effect measurements on granular aluminium insulating thin films. We have explored how the conductance relaxations induced by gate voltage changes depend on the age of the system, namely the time…
Insulating granular aluminum is one of the proto-typical disordered insulators whose low temperature electrical conductance exhibits ubiquitous non-equilibrium phenomena. These include slow responses to temperature or gate voltage changes,…
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…
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…
We present field effect measurements on discontinuous 2D thin films which are composed of a sub monolayer of nano-grains of Au, Ni, Ag or Al. Like other electron glasses these systems exhibit slow conductance relaxation and memory effects.…
In this article, we explore the temperature dependence of the electrical glassy dynamics in insulating amorphous indium oxide (a-InOx) and granular Al films. We use non-isothermal gate voltage protocols, which can reveal changes in the…
Transport measurements made on films of thallium-oxide (n-type semiconductor) are presented and discussed. The focus in this work is on the strongly-localized regime where charge transport is by variable-range-hopping. It is demonstrated…
We present a computer simulation study of a disordered two-dimensional system of localized interacting electrons at thermal equilibrium. It is shown that the configuration of occupied sites within the Coulomb gap persistently changes at…
Long range interactions are relevant for a wide range of phenomena in physics where they often present a challenge to theory. In condensed matter, the interplay of Coulomb interaction and disorder remains largely an unsolved problem. In two…
The emergence of glassy behavior of electrons is investigated for systems close to the disorder and/or interaction-driven metal-insulator transitions. Our results indicate that Anderson localization effects strongly stabilize such glassy…
We have recently found in insulating granular Al thin film a new experimental feature (Delahaye et al., Phys. Rev. Lett. 106, 186602, 2011), namely the existence of a conductance relaxation that is not sensitive to gate voltage changes.…
Slow conductance relaxations are observable in a many condensed matter systems. These are sometimes described as manifestations of a glassy phase. The underlying mechanisms responsible for the slow dynamics are often due to structural…
This paper describes the observation of non-equilibrium field effects at room temperature in four disordered insulating systems: granular Al, discontinuous Au, amorphous NbSi and amorphous InOx thin films. The use of wide enough gate…
Dramatic glass-like behavior involving nonexponential relaxation of in-plane electrical conduction, has been induced in quench-condensed ultrathin amorphous Bi films by the application of a parallel magnetic field. The effect is found over…
Properties of the "electron gas" - in which conduction electrons interact by means of Coulomb forces but ionic potentials are neglected - change dramatically depending on the balance between kinetic energy and Coulomb repulsion. The limits…
We focus on the slow relaxations observed in the conductance of disordered insulators at low temperature (especially granular aluminum films). They manifest themselves as a temporal logarithmic decrease of the conductance after a quench…