UCLA

Nanoscale heat conduction across tunnel junctions prepared through natural oxidation of metal electrodes is experimentally studied. The thermal resistance of AlOx tunnel barriers increases linearly with barrier thickness, which is consistent with the prevailing theory of heat conduction in highly disordered materials. Heat conduction across tunnel junctions is strongly impeded by finite thermal resistance at interfaces between barrier and electrode layers, which can be exploited to create superior thermal barrier coatings. The thermal conductivity of nanolaminates consisting of a series of Ta/TaOx tunnel junctions is determined to be well below the minimum thermal conductivity limit. (c) 2005 American Institute of Physics.