Delocalization of phonons and quantized thermal conductance in a randomn-mer system

Abstract

In this paper we report the phononic transport and its influence on thermal conductance in a one-dimensional random $n$-mer system. Based on an elastic wave equation, we studied frequency spectrum, phononic transmission, and thermal conductivity of the system. Multiple resonant transmissions are observed, which originate from delocalization of phonons in the correlated disorder system. At each resonant mode, zero-Lyapunov exponent and undecayed vibration of atoms have been found through the whole chain. Meanwhile channels are opened for phonon transmission and heat transport. As a result, thermal conductance is significantly enhanced at each resonant mode, forming a quantized feature as frequency increases. These properties demonstrate the possibility of manipulating phonon propagation and thermal conductance in phononic bandgap materials and may have potential applications in designing filter and waveguide for acoustic waves.