First-principles calculation of electronic structures and hyperfine interactions for muonium centers in ZnO

Abstract

The first-principles Hartree–Fock cluster method is applied to investigate the possible positions and associated hyperfine properties of the muonium centers in the II–VI semiconductor ZnO. Two clusters are used to simulate the local environments around the anti-bonding (AB) ∥ and bond-center (BC) ∥ muonium with axial symmetry along the c-axis, to try to understand the natures of the two centers whose axially symmetric hyperfine tensors have been observed experimentally. Our results show that the muonium center at the anti-bonding site close to oxygen (AB O) ∥ is more stable and its charge state is +0.44, which indicates a donor state in the semiconductor, but the associated hyperfine parameters are only in reasonable order of magnitude agreement with the experiments. The results for the (BC) ∥ center show a smaller binding energy than for the (AB O) ∥ center, and hyperfine parameters three orders of magnitude larger than the experiment but still an order of magnitude smaller than for free muonium.