Thermal spike model in the electronic stopping power regime

Abstract Two models have been proposed in order to explain the appearance of latent tracks induced in matter by the slowing down process of ions in the electronic stopping power regime. The first one was the thermal spike proposed by Desauer and reconsidered for metals by Seitz and Koehler. The second one was the ionic spike proposed by Fleischer et al in order to explain that metals are insensitive to the electronic excitation produced by fission fragment irradiations. In both models the key is the high mobility of the electrons in metals. The ionic spike model was considered as ineffective because of the too quick screening by the return electrons which inhibits a Coulomb impulse. In the thermal spike model the electronic energy was considered as spread out in a too large volume to induce a significant increase of the lattice temperature. Since that time a systematic use of heavy ion accelerators has enlarged the number of materials (metals, semiconductors and insulators) which present a defect creation induced by heavy ions in electronic stopping power (dE/dx) regime. Especially amorphous materials where the electron mobility is greatly reduced, are more sensitive than the same materials in their crystalline phase. Hence both models must be considered. D. Lesueur has reconsidered the ionic spike model while in this paper the thermal spike model will be revisited, enlightened by all the recent experiments using fs laser irradiations.