Electronic structure of bond-centred hydrogen and muonium in III–V compound semiconductors: Ab initio cluster calculations

Abstract

The molecular orbital model for bond-centred hydrogen or muonium in the III–V compound semiconductors is developed with the help of ab initio cluster calculations. The influence of the loss of symmetry in going from the elemental (group IV) to the compound (III–V) materials on the electronic structure is studied. The equilibrium configurations, potential energy surfaces and electronic structures of hydrogen or muonium near the bond-centred site in GaAs, GaP and InP are calculated at the ab initio HF level in the clusters Ga4As4H18 and the corresponding one for GaP and InP using a split-valence basis set and ab initio pseudopotentials for the core orbitals. First results of the calculations using a large Ga22As22H42 cluster are discussed. Preliminary results for InP indicate that ionization of the bond-centre defect may be considerably easier than in the other III–V compounds. which would explain why μSR-signals corresponding to the neutral Mu* state have not been detected in this material.