Tunable phonon resonances and thermal conductance in weakly nonlinear disordered systems with short-range correlation

National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University Nanjing 210093, China

Corresponding author: rwpeng@nju.edu.cn

Received: 11 April 2008
Accepted: 30 July 2008

Abstract

We theoretically investigate the resonant transmission of phonons and step-like thermal conductance in a weakly nonlinear generalized random n-mer (NGRN) system, where the impurity cluster with short-range correlation is randomly distributed in the host monatomic chain, and the atoms are connected by anharmonic potentials. The weakly anharmonic potential can be reduced to the quasi-harmonic form, which is tuned by external stretching. Due to the delocalization of phonons, resonant transmission is observed and thermal conductance presents a “quantized” feature. By applying external stretching on the NGRN system, the number of resonant modes and their locations are tuned. As a consequence, the “quantized” thermal conductance becomes tunable in this system. This finding may achieve potential applications in designing novel thermal-conducting materials.