Fermi surface of AuSb2. II. de Haas-van Alphen and de Haas-Shubnikov effects

de Haas-van Alphen and de Haas-Shubnikov oscillations were investigated in {100} and {110} planes of the metallic compound AuSb2. The orientation dependence of eight sets of external Fermi-surface areas was determined. These frequencies ranged from about 8×104 G to 5×107 G. Where the frequency and cyclotron mass data for the two experiments overlapped, the agreement was excellent. An attempt was made to compare the field dependence of the amplitude of one set of oscillations in the two experiments. The de Haas-Shubnikov data fit the theory for fields below about 75 kG but the de Haas-van Alphen data did not fit the theory for any field range down to about 20 kG, the lowest field at which the latter oscillations could be measured. These anomalies in field dependence seem to be connected with magnetic breakdown but the precise mechanism that could explain the apparently different breakdown fields seen in the two experiments is not clear. Two nearly free-electron models were constructed for the Fermi surface. These models assumed effective valences of 1 for gold and either 5 or 3 for antimony. However, since neither model was capable of explaining the orientation dependence of the extremal areas, it was concluded that the electronic structure of this compound is not nearly free-electron-like.