Ablation of GaAs by Intense, Ultrafast Electronic Excitation from Highly Charged Ions

We have measured total ablation rates and secondary ion yields from undoped GaAs(100) interacting with slow $(v=6.6\mathrm{}\times {10}^5\mathrm{m}/\mathrm{s})$, very highly charged ions. Ablation rates increase strongly as a function of projectile charge. Some 1400 target atoms are removed when a single ${\mathrm{Th}}^{70+}$ ion deposits a potential energy of 152.6 keV within a few femtoseconds into a nanometer-sized target volume. We discuss models for ablation of semiconductors by intense, ultrafast electronic excitation.