HEAT-TRANSPORT IN MESOSCOPIC SYSTEMS

Phonon heat transport in mesoscopic systems is investigated using meth ods analogous to the Landauer description of electrical conductance. A 'universal heat conductance' expression that depends on the propertie s of the conducting pathway only through the mode cutoff frequencies i s derived. Corrections due to reflections at the junction between the thermal body and the conducting bridge are found to be small except at very low temperatures where only the lowest few bridge modes are exci ted. Various non-equilibrium phonon distributions are studied: a narro w band distribution leads to clear steps in the cooling curve, analogo us to the quantized resistance values in narrow wires, but a thermal d istribution is too broad to show such features. (C) 1998 Academic Pres s Limited.