Precision measurements of cyclotron masses and Fermi velocities in the noble metals by the de Haas-van Alphen effect

Abstract

A total of 54 cyclotron masses have been determined with great precision from the temperature dependence of the de Haas-van Alphen (dHvA) amplitudes in the noble metals Cu, Ag, and Au. The accuracy of the data is ±0.3%. Special care was given to the temperature and amplitude measurements. In particular the influence of magnetic interaction and of the incomplete penetration of the modulation field into the high-purity samples, which were among the most serious sources of systematic errors, were eliminated. The mass data were deconvoluted to get values of the electron velocities $v^{*}\left(\overrightarrow{\mathrm{k}}\right)$ for each point on the Fermi surfaces. The qualitative behavior of $v^{*}\left(\overrightarrow{\mathrm{k}}\right)$ agrees with that found in previous works, but the absolute values differ by as much as 10%. Local values of the electron-phonon enhancement factor, $1+\lambda \left(\overrightarrow{\mathrm{k}}\right)$, were obtained in Cu by comparing velocities deduced from dHvA cyclotron masses which include electron-phonon renormalization with band velocities deduced from a band-structure calculation. Cyclotron masses were calculated for about 40 orbits not measured in each of the three metals. The coefficient of electronic specific heat was calculated from the experimental data. The agreement with the data obtained from specific-heat measurements is excellent.