Fermi Surface of Beryllium and Its Pressure Dependence

The Fermi surface of beryllium has been throughly investigated by means of the de Haas-van Alphen effect, and the frequencies, though substantially in agreement with earlier measurements, have been obtained to greater accuracy. This has made it possible to construct a nonlocal pseudopotential model for the Fermi surface, in which the Fourier coefficients of the crystal potential are treated as parameters to be evaluated by fitting to the experimental data. In this way, all the principal cross sections of the surface have been fitted to within 1%, using only five adjustable parameters. Comparison of calculated cyclotron masses for these cross sections with the masses determined from the temperature dependence of the dHvA amplitudes indicates that the mass is enhanced about 20% by many-body interactions neglected in the model. Finally, the pressure dependence of the Fermi surface has been calculated and compared with some available experimental measurements.