I am interested in the physics of novel effects in nanoscale systems. My recent work falls in three broad categories: submicron electronic devices, heat transport in on the molecular scale, and two dimensional electron gasses.
Solid state systems on the nanoscale are in between the regimes of classical and quantum physics. Experimentalists can routinely fashion devices so small that the electrostatic energy of a single electron can control the flow of current, or in which electrons can travel coherently from one side of the device to the other. The theoretical challenges are to understand how the quantum mechanical effects in the microscopic device couple to macroscopic world of voltmeters and ammeters, and how to take advantage of the novel dynamics for new applications.
Heat transport in small devices and nano-composites is also often not diffusive. In order to understand how energy flows through such systems we have to go beyond a Boltzmann equation approach and look at the dynamics of the electron and phonon modes. Careful control of material properties on the nanometer scale can enable us to design devices and materials with novel thermal and electrical properties.
My third area of interest is the dynamics on electrons when they are confined to a two dimensional plane. This leads to a host of interesting topics including localization, unusual behavior in a strong magnetic field, and the existence of electron "bubbles" called skyrmions.
"Using normal modes to calculate and optimize thermal conductivity in functionalized macromolecules," Abdellah Ait Moussa and Kieran Mullen, Phys. Rev. E, 83, 056708, (2011) ADS: 2011PhRvE..83e6708A
"R-Matrix Theory for Nanoscale Phonon Thermal Transport across Devices and Interfaces," K.G.S.H. Gunawardana, K. Mullen, Numerical Heat Transfer, Part B: Fundamentals, 60(4), 235-251, (2011) DOI: 10.1080/10407790.2011.609124
"Optimal Matching of Thermal Vibrations into Carbon Nanotubes," K.G.S.H. Gunawardana and K. Mullen, Proceedings of 41st ISTC - Wichita, KS, (SAMPE Journal, 2009)
"Theory of Activated Transport in Bilayer Quantum Hall Systems," B. Roostaei, K. J. Mullen, H. A. Fertig, and S. H. Simon, Phys. Rev Lett., 101, 046804, (2008) ADS: 2008PhRvL.101d6804R
"Polarization transitions in interacting ring 1D arrays," Bahman Roostaei and Kieran J. Mullen, Phys. Rev. B, 78, 075411, (2008) ADS: 2008PhRvB..78g5411R
"Calculated Thermal Properties of Single-Walled Carbon Nanotube Suspensions," Hai M. Duong, Dimitrios V. Papavassiliou, Kieran J. Mullen, Brian L. Wardle, and Shigeo Maruyama, J. Phys. Chem. C, 112(50), 19860–19865, (2008) DOI: 10.1021/jp710021n