RESONANT AC CONDUCTING SPECTRA IN QUASIPERIODIC SYSTEMS

Based on the Kubo-Greenwood formula, a renormalization plus convolution method is developed to investigate the frequency-dependent electrical conductivity of quasiperiodic systems. This method combines the convolution theorem with the real-space renormalization technique which is able to address multidimensional systems with 1024 atoms. In this article, an analytical evaluation of the Kubo-Greenwood formula is presented for the ballistic ac conductivity in periodic chains. For quasiperiodic Fibonacci lattices connected to two semi-infinite periodic leads, the electrical conductivity, is calculated by using the renormalization method and the results show that at several frequencies, their ac conductivities could be larger than the ballistic ones. This fact might be related to the resonant scattering process in quasiperiodic systems. Finally, calculations made in segmented Fibonacci nanowires reveal that this improvement to the ballistic ac conductivity via quasiperiodicity is also present in multidimensional systems.