Berlin 2008 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 10: Glasses III (joint session DF/DY)

DF 10.4: Talk

Wednesday, February 27, 2008, 15:15–15:30, EB 407

Conductivity of Alkali Glasses in Quantum Statistics — •Joachim Sohns and Michael Schulz — University of Ulm

Our aim is to find an analytically solvable model of the conductivity of mixed alkali glasses. Our starting point is the schroedinger equation of the multy particle wave function of the system. As a consequence of the structural and dynamical disorder the system is irreversible in time. The dynamics of the system is given by the matrix greens functions of the keldysh technique. The linear response of the system to an external electrical field may be calculated within the kubo formalism. In addition to the usual paramagnetic and diamagnetic current we find an other contribution to the current which is caused by the finite life times of the states. The dependence of the conductivity on the concentration of alkali ions, on the temperature and on the frequency of the external electrical field are calculated. The mixed alkali effect is reproduced by our model.