Observation of a large ground-state splitting in the infrared absorption spectrum of Zn in Ge

Abstract
The temperature dependence of the infrared absorption spectrum of the double acceptor Zn in Ge reveals a large ground-state splitting of ≈2.4 meV, which is in good agreement with a splitting postulated from a reexamination of the photoluminescence spectrum of Ge: Zn. It has long been assumed that the ground state of the Zn double acceptor was not split, and the detection of this large splitting will necessitate a reevaluation of previous results. The thermalization of the recently reported fine structure of the Ge: Be spectrum was also observed between 7 and 1.3 K.