Magnetoresistance of the metallic compounds Cu₂Sb and YZn to 220 kG

Topological properties of the Fermi surfaces of Cu₂Sb and YZn have been investigated. Cu₂Sb is a compensated metal with open orbits in [001], 〈100〉, 〈011〉, and several higher-order directions. The results are consistent with the nearly-free-electron Fermi surface model. In YZn the data indicate that there is an open sheet of Fermi surface which supports open orbits in 〈110〉 and/or 〈100〉 directions. This conclusion, along with de Haas-van Alphen results of Jan, provides evidence for the topological accuracy of one of two recent augmented-plane-wave, band-structure calculations; the two calculations predict quite different Fermi surfaces.