Kieran Mullen

Computational modeling of the thermal conductivity of single-walled carbon nanotube–polymer composites

A computational model was developed to study the thermal conductivity of single-walled carbon nanotube (SWNT)-polymer composites. A random walk simulation was used to model the effect of interfacial resistance on the heat flow in different orientations of SWNTs dispersed in the polymers. The simulation is a modification of a previous model taking into account the numerically determined thermal equilibrium factor between the SWNTs and the composite matrix material. The simulation results agreed well with reported experimental data for epoxy and polymethyl methacrylate (PMMA) composites. The effects of the SWNT orientation, weight fraction and thermal boundary resistance on the effective conductivity of composites were quantified. The present model is a useful tool for the prediction of the thermal conductivity within a wide range of volume fractions of the SWNTs, so long as the SWNTs are not in contact with each other. The developed model can be applied to other polymers and solid materials, possibly even metals.

Random walks in nanotube composites: Improved algorithms and the role of thermal boundary resistance

Random walk simulations of thermal walkers are used to study the effect of interfacial resistance on heat flow in randomly dispersed carbon nanotube composites. The adopted algorithm effectively makes the thermal conductivity of the nanotubes themselves infinite. The probability that a walker colliding with a matrix-nanotube interface reflects back into the matrix phase or crosses into the carbon nanotube phase is determined by the thermal boundary (Kapitza) resistance. The use of “cold” and “hot” walkers produces a steady state temperature profile that allows accurate determination of the thermal conductivity. The effects of the carbon nanotube orientation, aspect ratio, volume fraction, and Kapitza resistance on the composite effective conductivity are quantified.

Pseudospin vortex-antivortex states with interwoven spin textures in double-layer quantum Hall systems

Recent experiments on strongly correlated bilayer quantum Hall systems strongly suggest that, contrary to the usual assumption, the electron spin degree of freedom is not completely frozen either in the quantum Hall or in the compressibles states that occur at filling factor

R-Matrix Theory for Nanoscale Phonon Thermal Transport across Devices and Interfaces

\ensuremath{\nu}=1

Theory of Activated Transport in Bilayer Quantum Hall Systems

. These experiments imply that the quasiparticles at

Theory of tunneling resonances of bilayer electron systems in a strong magnetic field

\ensuremath{\nu}=1

Time-evolution of the GaAs(0 0 1) pre-roughening process

could have both spin and pseudospin textures; i.e., they could be

Thermodynamic phase diagram of the quantum hall skyrmion system

{\mathit{CP}}^{3}

Anisotropic transport of quantum Hall meron-pair excitations

Skyrmions. Using a microscopic unrestricted Hartree-Fock approximation, we compute the energy of several crystal states with spin, pseudospin, and mixed spin-pseudospin textures around

Mullen, Uchoa, and Glatzhofer Reply.

\ensuremath{\nu}=1