INTERMEDIATE-WAVELENGTH CYCLOTRON WAVES IN SIMPLE METALS AND FERMI-LIQUID EFFECTS

In this paper we explore the propagation of cyclotron waves of intermediate wavelength in a simple metal with a spherical Fermi surface. We show experimentally how thick plates of potassium metal can be used to study the lowest branch of the multivalued dispersion relation and to find the locations of turning points on the dispersion curve. The methods employed allow the dispersion curve to be studied at relatively large wave vectors, a region in which the Fermi-liquid parameter A1 can produce observable modifications. Although the present experiments agree well with a free-electron model, we present numerical calculations showing the effects of A1 and A2 on the dispersion curve and note in particular the circumstances under which one should be able to determine A1 experimentally. © 1979 The American Physical Society.