Nonequilibrium Green’s Function Approach to Phonon Transport in Defective Carbon Nanotubes

Abstract

We have developed a new theoretical formalism for phonon transport in nanostructures using the nonequilibrium phonon Green's function technique and have applied it to thermal conduction in defective carbon nanotubes. The universal quantization of low-temperature thermal conductance in carbon nanotubes can be observed even in the presence of local structural defects such as vacancies and Stone-Wales defects, since the long wavelength acoustic phonons are not scattered by local defects. At room temperature, however, thermal conductance is critically affected by defect scattering since incident phonons are scattered by localized phonons around the defects. We find a remarkable change from quantum to classical features for the thermal transport through defective CNTs with increasing temperature.

Electron and phonon transport in silicon nanowires: Atomistic approach to thermoelectric properties

“…9 For relatively short disordered wires, the anharmonicity effect is thus of limited importance. The phonon thermal current at temperature T can be calculated from the transmission function as [25][26][27] …”

Coupled electron and phonon transport in one-dimensional atomic junctions

“…In both cases, the quantum effect becomes important 1 . Only recently, the nonequilibrium Green's function method 9,10,11,12 , which has been widely used to study the electronic transport, has been applied to study the quantum phononic transport 13,14,15,16,17 . As far as we know, the study of the coupled electronic and phononic transport in nanostructures is rare 18,19,20,21 .…”

Phonon Transport in Isotope-Disordered Carbon and Boron-Nitride Nanotubes: Is Localization Observable?

“…One specific issue that is still controversial is the effect of isotope disorder on nanotube thermal conduction, which has been experimentally investigated in boron-nitride (BN) nanotubes (NTs) [2]. Despite the fact that thermal transport in disordered quasi-one-dimensional (1D) systems has been addressed in several theoretical studies [3][4][5][6][7][8][9][10][11][12][13][14], a detailed analysis of this problem in realistic systems at the atomic scale is still lacking. Previous work has focused on short nanowires (NWs) and thin films with rough surface [3][4][5][6][7][8] and isotope impurities [9].…”