Impact ionization and intervalley electron scattering in InSb and InAs induced by a single terahertz pulse.

Electronic properties of InSb and InAs are sensitive to electric field due to their narrow forbidden energy gaps and big difference in effective masses of electrons in different conduction band valleys. Here we report impact ionization processes and redistribution of electrons between the Γ, L and X valleys induced by a single ultrashort terahertz (THz) pulse at 80 K temperature. Monte Carlo simulation revealed that electron motion in this case has near ballistic character.