AC conductivity and the anomalous dielectric constant of a disordered two-dimensional system

Donita Ben-Zimra, Moshe Kaveh

Research output: Contribution to journalArticlepeer-review

Abstract

The authors calculate the AC conductivity for a disordered two-dimensional system and find a transition between diffusive-like behaviour and hopping-like behaviour. In the diffusive region, (r2) approximately tw with w<1 and sigma diff approximately omega 1-w. This behaviour is found to be consistent with power-law localisation with w=1/(1+s) where s is the exponent of the power-law wavefunction, mod psi mod approximately r-s. In the hopping region, the authors find sigma hop approximately omega 2-3s/. This leads to an anomalous dielectric constant epsilon 1 which diverges at two values of energy, at the mobility edge and at an energy for which s=3. For s>3, epsilon 1 is finite and positive down to the mobility edge Ec. Below Ec, the dielectric constant diverges as epsilon 1 approximately (Ec-E)-(4 nu -1) where nu is the exponent of the localisation length xi approximately (Ec-=E)- nu.

Original languageEnglish
Pages (from-to)83-89
Number of pages7
JournalJournal of Physics C: Solid State Physics
Volume20
Issue number1
DOIs
StatePublished - 10 Jan 1987

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