Positron Blocking from Muon Decay in Silicon

Abstract

This paper reports the observation of the blocking effect of the host lattice on decay positrons from positive muons implanted into silicon crystals. High-purity and oxygen-doped wafers with [110] and [111] orientations were investigated, and axial and planar effects were seen both as blocking dips and as flux peaks. The results, together with muon spin-rotation experiments on the same samples, indicate a low-symmetry muonium state in pure material and an oxygen-trapped muonium state at a tetrahedral site in doped material.