Using the non-equilibrium Green’s function techniques with interatomic potentials, we study the temperature dependence and the crossover of thermal conductance from the usual behavior proportional to the cross-sectional area at room temperature to the universal quantized behavior at low temperature for carbon nanotubes, silicon nanowires, and diamond nanowires. We find that this crossover of th...

We present a theoretical scheme that seamlessly handles the crossover from fully ballistic to diffusive thermal transport regimes and apply it to carbon nanotubes. At room temperature, the micrometer-length nanotubes belong to the intermediate regime in which ballistic and diffusive phonons coexist, and the thermal conductance exhibits anomalous nonlinear tube-length dependence due to this coex...

The effect of phonon scattering by surface roughness on the thermal conductance in mesoscopic systems at low temperatures is calculated using full elasticity theory. The low frequency behavior of the scattering shows novel power law dependences arising from the unusual properties of the elastic modes. This leads to new predictions for the low temperature depression of the thermal conductance be...

Body size is one of the most important determinants of energy metabolism in mammals. However, the usual physiological variables measured to characterize energy metabolism and heat dissipation in endotherms are strongly affected by thermal acclimation, and are also correlated among themselves. In addition to choosing the appropriate measurement of body size, these problems create additional comp...

We explain the reduction of the thermal conductance below the predicted universal value observed by Schwab et al.1 in terms of the scattering of thermal phonons off surface roughness using a scalar model for the elastic waves. Our analysis shows that the thermal conductance depends on two roughness parameters: the roughness amplitude δ and the correlation length a. At sufficiently low temperatu...

We have investigated the effect on phonon energy transport in mesoscopic systems and the reduction in the thermal conductance in the quantum limit due to phonon scattering by surface roughness, using full threedimensional elasticity theory for an elastic beam with a rectangular cross section. At low frequencies, we find power laws for the scattering coefficients that are strongly mode dependent...

Several heat transfer problems related to single-walled carbon nanotubes (SWNTs) are considered using molecular dynamics (MD) simulations. The Brenner potential (Brenner, 1990) with the simplified form (Yamaguchi and Maruyama, 1998) is employed as the potential function between carbon and carbon within a nanotube. MD simulations of thermal conductivity along a nanotube, isotope effect in longit...

Thermal interface conductance was measured for soluble gold nanorods (NRs) coated with mercaptocarboxylic acids (HS-(CH(2))(n)COOH, n = 5, 10, 15), thiolated polyethylene glycols (MW = 356, 1000, 5000), and HS-(CH(2))(15)-COOH-coated NRs further coated with alternating layers of poly(diallyldimethylammonium chloride) and poly(sodium styrenesulfonate). Ferguson analysis determined ligand thickne...

We have developed an efficient order-N real space Kubo approach for the calculation of the phonon conductivity which outperforms state-of-the-art alternative implementations based on the Green’s function formalism. The method treats efficiently the time-dependent propagation of phonon wave packets in real space, and this dynamics is related to the calculation of the thermal conductance. Without...

The novel thermal conductance mechanism, theoretically predicted and experimentally measured in nanotube field-effect transistors (FET), is discussed with respect to the power dissipation problem of modern carbon-based electronics. Such an effect is due to the near-field coupling of the charge carriers in the transistor channel with the local electric field of the surface electromagnetic modes....