CONDUCTIVITY OF 2D LATTICE ELECTRONS IN AN INCOMMENSURATE MAGNETIC-FIELD

We consider conductivities of two-dimensional lattice electrons in a m agnetic field. We focus on systems where the flux per plaquette phi is irrational (incommensurate flux). To realize the system with the inco mmensurate flux, we consider a series of systems with commensurate flu xes which converge to the irrational value. We have calculated a real part of the longitudinal conductivity sigma(xx)(omega). Using a scalin g analysis, we have found R sigma(xx)(omega) behaves as 1/omega(gamma) (gamma = 0.55) when phi = tau, (tau = root 5-1/2) and the Fermi energ y is near zero. This behavior is closely related to the known scaling behavior of the spectrum.