Tunable phonon resonances and thermal conductance in weakly nonlinear disordered systems with short-range correlationL. S. Caot, R. W. Peng, De Li, Xin Wu, D. X. Qi, Feng Gao and Mu Wang
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University Nanjing 210093, China
received 11 April 2008; accepted in final form 30 July 2008; published September 2008
published online 8 September 2008
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.
63.50.-x - Vibrational states in disordered systems.
43.40.+s - Structural acoustics and vibration.
61.43.-j - Disordered solids.
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