Phonon group velocity and thermal conduction in superlattices

Coherent phonon heat conduction in superlattices.

The control of heat conduction through the manipulation of phonons as coherent waves in solids is of fundamental interest and could also be exploited in applications, but coherent heat conduction has not been experimentally confirmed. We report the experimental observation of coherent heat conduction through the use of finite-thickness superlattices with varying numbers of periods. The measured...

Superlattices and Microstructures (2015), Preprint PHONON THERMAL CONDUCTIVITY OF GRAPHENE

The study of graphene thermal conductivity is of great importance, as its anomalous thermal and electrical conductivities (the largest among the all known materials so far) provide very good perspectives for graphene-based nanoelectronics devices. Thermal conductivity of graphene is phonon-based, since its electronic-based thermal conductivity represents less than 1% of the total thermal conduc...

Thermal conduction in lattice–matched superlattices of InGaAs/InAlAs

Phonon-induced polariton superlattices.

We show that the coherent interaction between microcavity polaritons and externally stimulated acoustic phonons forms a tunable polariton superlattice with a folded energy dispersion determined by the phonon population and wavelength. Under high phonon concentration, the strong confinement of the optical and excitonic polariton components in the phonon potential creates weakly coupled polariton...

Decomposition of coherent and incoherent phonon conduction in superlattices and random multilayers

Nonequilibrium molecular dynamics (NEMD) simulations on conceptual binary Lennard-Jones systems show that the thermal conductivity (κ) of a superlattice (SL) can be significantly reduced by randomizing the thicknesses of its layers, by which a SL becomes a random multilayer (RML). Such reduction in κ is a clear signature of coherent phonon that can be localized in RMLs. We build a two-phonon mo...