Transverse Breakdown in a Strong Hall Electric Field

Abstract

Impact ionization of electron-hole pairs by hot electrons, which exist when a strong Hall electric field is present, is proposed. Theoretical arguments indicate that the saturated value of the Hall electric field should coincide with the breakdown electric field in a sample whose Hall electric field is shorted. Experiments substantiate this. The existence of electrons and holes in the region of applied field where the Hall electric field saturated was demonstrated by the decrease of resistance between the Hall contacts, as well as by the observation of a strong Suhl effect in a wide sample. The observed decrease in the Hall electric field just above the onset of ionization is related to the contribution of the holes to the Hall field. Thus, the drift-velocity saturation in strong crossed electric and magnetic fields is explained in consistent fashion as due to impact ionization occurring primarily in the E\ifmmode\times\else\texttimes\fi{}B direction.