Thermal interface conductance between aluminum and aluminum oxide: A rigorous test of atomistic level theories
Abstract
We report the first ever accurate theoretical prediction of thermal conductance of any
material interface. Thermal interfacial conductance of aluminum (Al)-sapphire (α-Al2O3) interface
along crystal directions (111) Al || (0001) Al2O3 for temperature ranging from 50-500 K is
calculated using two fundamentally different methods: interfacial conductance modal analysis
(ICMA) and atomistic green function (AGF). While AGF overpredicts interfacial conductance,
both the quantitative and qualitative predictions of ICMA are exceptional when compared with the
time-domain thermoreflectance (TDTR) experimental data. The mean error in ICMA results are
below 5%. We believe that the accurate theoretical prediction by ICMA can be credited to a more
fundamental treatment of the interfacial heat flux in contrast to that of the phonon gas model
(PGM) and inclusion of anharmonicity to full order. ICMA also gives the eigen mode level details
revealing the nanoscale picture of heat transport: more than 90% of conductance is contributed by
the cross correlation (interaction) between partially extended modes of Al and Al2O3 and the
remaining is attributed to interfacial modes. This is a major milestone in combustion heat transfer
research enabling materials scientists to rationally design propellant architectures to serve longdistance
propulsion missions.