Related papers: The Frequency Dependent Conductivity of Electron G…
Optical measurements of the real and imaginary frequency dependent conductivity of uncompensated n-type silicon are reported. The experiments are done in the quantum limit, $ \hbar\omega > k_{B}T$, across a broad doping range on the…
We report measurements of the real and imaginary parts of the AC conductivity in the quantum limit, \hbar \omega > k_B T of insulating nominally uncompensated n-type silicon. The observed frequency dependence shows evidence for a crossover…
Characterizing the frequency-dependent response of amorphous systems and glasses can provide important insights into their physics. Here, we study the response of an electron glass, where Coulomb interactions are important and have…
Electronic transport in highly doped but still insulating silicon at low temperatures is dominated by hopping between localized states; it serves as a model system of a disordered solid for which the electronic interaction can be…
We have conducted temperature and frequency dependent transport measurements in amorphous Nb_x Si_{1-x} samples in the insulating regime. We find a temperature dependent dc conductivity consistent with variable range hopping in a Coulomb…
The out-of-equilibrium excess conductance of electron-glasses typically relaxes with a logarithmic time-dependence. Here it is shown that the log(t) relaxation of a weakly-disordered amorphous indium-oxide films crosses-over asymptotically…
The response of ionic solutions to time-varying electric fields, quantified by a frequency-dependent conductivity, is essential in many electrochemical applications. Yet, it constitutes a challenging problem due to the combined effect of…
We study the optical conductivity of a pristine two-dimensional electron system near an Ising-nematic quantum critical point. We discuss the relation between the frequency scaling of the conductivity and the shape of the Fermi surface,…
We study the doping of a Mott insulator in the presence of quenched frustrating disorder in the magnetic exchange. A low doping regime $\delta<J/t$ is found, in which the quasiparticle coherent scale is low : $\epsilon_F^* = J…
Iridates provide a fertile ground to investigate correlated electrons in the presence of strong spin-orbit coupling. Bringing these systems to the proximity of a metal-insulator quantum phase transition is a challenge that must be met to…
We consider the combined influence of disorder, electron-electron interactions and quantum hopping on the properties of electronic systems in a localized phase, approaching an insulator-metal transition. The generic models in this regime…
The time-dependent fluctuations of conductivity \sigma have been studied in a two-dimensional electron system in low-mobility, small-size Si inversion layers. The noise power spectrum is ~1/f^{\alpha} with \alpha exhibiting a sharp jump at…
We study the Coulomb glass emerging from the interplay of strong interactions and disorder in a model of spinless fermions on the Bethe lattice. In the infinite coordination number limit, strong interactions induce a metallic Coulomb glass…
At low energy scales charge transport in the insulating Si:P is dominated by activated hopping between the localized donor electron states. Thus, theoretical models for a disordered system with electron-electron interaction are appropriate…
Using Brownian dynamics simulations, we investigate the effects of confinement, adsorption on surfaces and ion-ion interactions on the response of confined electrolyte solutions to oscillating electric fields in the direction perpendicular…
Millimeter-wave transmission measurements have been performed in amorphous niobium-silicon alloy samples where the DC conductivity follows the critical temperature dependence $\sigma_{dc} \propto T^{1/2}$. The real part of the conductivity…
We investigate a symmetry protected $Z_2$ topological electron glass -- a glassy equivalent of the $Z_2$ topological band insulator in crystalline systems -- and uncover associated quantum phase transitions in this three dimensional…
We study models of itinerant spinless fermions with random long-range interactions. We motivate such models from descriptions of fermionic atoms in multi-mode optical cavities. The solution of an infinite-range model yields a metallic phase…
We study the time-dependent conductance of electron-glasses excited by electromagnetic radiation at microwaves (MW) and infra-red frequencies. In either case the conductance G is enhanced during exposure but its time dependence after the…
Glassy behavior is a generic feature of electrons close to disorder-driven metal-insulator transitions. Deep in the insulating phase, electrons are tightly bound to impurities, and thus classical models for electron glasses have long been…