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HL: Fachverband Halbleiterphysik

HL 52: Transport properties

HL 52.9: Talk

Friday, March 30, 2007, 13:00–13:15, H14

Microwave investigations of electronic correlations in the electron glass Si:P — •Elvira Ritz and Martin Dressel — 1.Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany

Electronic correlations influence the charge transport in Si:P at low energy scales. We study the frequency-dependent complex conductivity of Si:P in a large range of phosphorus concentrations below the metal-insulator transition (MIT). At low temperatures (down to 1.2 K) and low frequencies (50 MHz - 20 GHz) the charge transport in the insulatig Si:P is by hopping between the impurity sites with localized electronic states. The electrodynamic response of this system serves as a model for the so-called electron glasses. The effects of the electron-electron interactions is a crucial issue. We observe the power law corresponding to the Coulomb glass in the lower part of the conductivity spectrum as well as a frequency independent permittivity with a critical behavior in the vicinity of the MIT. The temperature dependence of the dynamical response is also discussed.