Heat Transport:

Due to the increasing importance of heat management issue in nanoscale and thermoelectric devices, this field has recently become very active. Also, from a fundamental perspective, heat propagation in low-dimensional systems is anomalous and behaves differently from charge conduction. Our research is focused on mainly two areas:

Lattice Thermal Conductivity from First-Principles:

At high temperatures, umklapp (inelastic phonon-phonon) scattering dominates the thermal resistivity. We are thus trying to calculate anharmonic force constants from ab-initio calculations. They can then be used to compute thermal conductivity of several materials at least in their bulk phase. The next step would be to perfom the same calculations for  restricted geometries, interfaces and nanoscale systems.

My most recent research concerns developing a method to compute cubic and quartic anharmonic force constants from first-principles density-functional calculation. They will be used in the computation of thermal conductivity and can also be the basis of a classical interatomic potential of ab-initio accuracy for performing molecular dynamics simulations.

Dynamics of heat transport in one-dimensional FPU systems:

We use molecular dynamics simulations to compute the wavevector and frequency-dependent thermal conductivity of anharmonic lattices to investigate the effect of integrability as well as that of impurities/disorder on the frequency-dependence. This work is being done in collaboration with S. Shastry and P. Young.