Thermal Rectification\nin Telescopic Nanowires: Impact\nof Thermal Boundary Resistance

A thermal diode, which, by analogy to its electrical\ncounterpart,\nrectifies heat current, is the building block for thermal circuits.\nTo realize a thermal diode, we demonstrate thermal rectification in\na GaAs telescopic nanowire system using the thermal bridge method.\nWe measured a preferred direction of heat flux, achieving rectification\nvalues ranging from 2 to 8% as a function of applied thermal bias.\nWe demonstrate that the thermal boundary resistance between the thin\npart with the wurtzite crystal phase and the thick part with the zinc-blende\ncrystal phase of the telescopic nanowire plays a crucial role in determining\nthe amount and direction of heat flux rectification. This effect is\nconfirmed by numerical solutions of the one-dimensional heat equation\nbased on ab initio data. Additionally, we accounted for the effect\nof the thermal contact resistance. This work is the first experimental\nindication of rectification using a telescopic nanowire where we reveal\nthe importance and role of the thermal boundary resistance in determining\nthermal rectification.