BOND-CENTERED HYDROGEN AND MUONIUM IN SILICON - A FEYNMAN PATH-INTEGRAL SIMULATION

Isolated hydrogen and muonium in crystalline silicon have been studied by the path-integral Monte Carlo method, using a parametrized Si-H in teraction derived from earlier ab initio calculations. Hydrogen and de uterium are found to be stable at the bond-centre (BC) site, but this position is metastable for muonium. Average values of the kinetic and potential energy of the defects are compared with those expected for t he hydrogen-like impurities within a harmonic approximation. The backw ards relaxation of the Si-atom nearest neighbours of the impurity is f ound to be dependent on the impurity mass (higher host-atom relaxation for higher impurity mass).