Zeeman and Piezo-Zeeman spectroscopy of acceptors in germanium

A brief review is given of the Zeeman and piezo-Zeeman results for the spectra of shallow acceptors in germanium. Also included are new data for the Zeeman spectra of thallium with B ∥〈100〉 and boron, gallium and thallium under B ∥〈111〉. The observations are for field strengths up to 7T and the results compared with recent calculations of these effects. New data for neutral zinc in germanium with B ∥〈100〉 is also indicated.