Thermal conductivity of Al2O3 irradiated with swift heavy ions

•Comprehensive study of thermal conductivity under swift heavy ion irradiation.•Very strong effect of a narrow highly damaged track core on heat propagation.•Classical thermal transport model may be not valid for nanometric SHI tracks. Thermal transport in α-Al2O3 irradiated with 167 MeV Xe ions is studied within direct method based on the Fourier law implemented into classical molecular dynamics. Formation of defective regions as a result of ion passages is described using the original multiscale approach developed in previous works. Degradation of the thermal conductivity coefficient of single-crystalline alumina with ion fluence shows reasonable agreement with the experimental thermoreflectance data. The applied method demonstrated good applicability in the considered case and allowed to distinguish effects of discontinuous crystalline tracks on thermal conductivity of the alumina target. It was surprisingly observed that a nanometric highly damaged core of swift heavy ion tracks strongly affect the heat transport in the irradiated material, which is in contradiction with classical Rayleigh model.