Determination of the Size of the "Necks" in Fermi Surfaces of Even-Valence Metals: Application to Lead

Abstract

A technique is described which permits a precise measurement of features in the magnetoresistance which are directly related to the Fermi surface "neck" size of even-valence metals. The axis of the sample is tipped through a precisely known angle, by means of a goniometer arc, causing the disappearance of cusp-like troughs which indicate the boundaries of the particular features. The dimensions of these features are determined for Pb within uncertainties an order of magnitude smaller than those of previous measurements. The neck size for Pb, as calculated within the framework of Gold's free-electron model for the Fermi surface, is $0.29b$, where $b$ is the period of the reciprocal lattice.