Line Shape of Cyclotron Resonance in N-Type Germanium at 337μm in the Temperature Range 15–100 K

Abstract

Recently, an influence of the non-para = bolicity of the conduction band of n-type Ge on the position of the transvers-mass cyclotron resonance was observed in far-infrared experiments [1,2]. Like in a magnetopiezotransmission experiment [3] the results seemed indicate that the non-parabolicity is stronger than calculated [3]. In the calculations only two bands - the L 1 conduction band and the L 3 , valence band - were taken into account. A more refined theory [4] including 15 bands did not yield significant corrections. So, it was difficult to understand what might cause the strong non-parabolicity as observed in the experiments. It is the purpose of this work to show that the inclusion of the k H dependence in the a.c. conductivity which has been neglected so far removes the discrepancy. Furthermore, we show that it is necessary to take into account the non-parabolicity for an exact interpretation of cyclotron resonance line shapes although this effect is much smaller than in semicon ductors like n-InSb.