NON-OHMIC CONDUCTION IN GERMANIUM UNDER A STRONG MAGNETIC FIELD

A distinct non-ohmic current-voltage characteristics in n-type germanium containing 1020 to 1022 impurity atoms/m3under a strong impulsive magnetic field was found at liquid hydrogen temperatures. The effect was also observed in p-type germanium with appropriate impurity concentrations for the transverse magnetic field stronger than 1 Wb/m2. Essential mechanism underlying this effect would be a “transverse breakdown” introduced by M. Toda et al. In the present case, however, “transverse impact ionization” should be more appropriate than “transverse breakdown”. Necessary conditions for the occurrence of this non-ohmic effect are (1) the existence of the strong Hall field and (2) neutralized donors or acceptors in germanium crystals. Some peculiar phenomena associated with this effect i.e., a kind of instability in electric current, negative differential drift mobility and the anomalous electric field dependence of the Hall angle were also observed. © 1969, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.