| Popis: |
The Fermi surface of indium was investigated using the Doppler-shifted acoustic cyclotron resonance method. The measurements are sensitive to small changes in the shape of the Fermi surface and, hence, are a good measure of the deviations of the Fermi surface from the free-electron model. The attenuation of short pulses of longitudinal sound, with a frequency between 100 MHz and 300 MHz, in single crystal indium was measured in the presence of a varying magnetic field. Values of the magnetic field at which peaks in the acoustic absorption were observed are related to the rate of change of the area of the cross section of the Fermi surface normal to the magnetic field with respect to the component of the electron wave-vector parallel to the magnetic field. The shape of the Fermi surface of indium in the third Brillouin zone is in question. Most investigators have not observed the alpha-arms of the Fermi surface in the third zone predicted by the free-electron model. As a consequence, the existence of the alpha-arms has been considered doubtful. However, the observations of this investigation can be interpreted consistently only if the alpha-arms are assumed to exist. A limited investigation was made of the dependence of the heights of the absorption resonance peaks on temperature, magnetic field and sonic wave number. The results of these measurements await the development of a general theory of Doppler-shifted acoustic cyclotron resonance for comparison with theoretical predictions. (Author) |
