Tunable thermal conductivity in defect engineered nanowires at low temperatures

We measure the thermal conductivity (kappa) of individual InAs nanowires (NWs), and find that it is three orders of magnitude smaller than the bulk value in the temperature range of 10-50 K. We argue that the low kappa arises from the scattering of phonons in the random superlattice of twin defects oriented perpendicular to the axis of the NW. We observe a significant electronic contribution arising from the surface accumulation layer, which gives rise to the tunability of kappa with the application of an electrostatic gate and a magnetic field. Our devices and measurements of kappa at different carrier concentrations and magnetic field offer a means to study unique aspects of nanoscale thermal transport.