Role of Negative Effective Mass in Negative Resistance

Experiments on cyclotron resonance of negative-mass carriers in Ge have been reported. The distribution of carriers is not an equilibrium distribution, since the carriers were produced by optical excitation partly from acceptors and partly across the gap. A new resonance is found for the opposite sense of circular polarization to the positive-mass resonance line and the resonance corresponds to a decreased absorption. The relationship between negative effective mass, carrier distribution, and negative resistance is investigated. (W.D.M.)