Positively charged muonium centers in aluminum and gallium nitrides

Abstract

The Mu + defect centers in AlN and GaN are studied using muon nuclear-quadrupole level-crossing resonance (QLCR) and zero-field muon spin depolarization measurements. The dominant Mu + center is highly mobile, but QLCR spectra identify a second static Mu + state at AB ||(N) sites in both nitrides. This state becomes mobile above 800 K in AlN, but converts to a Mu − above 200 K in GaN. Zero-field data characterize local fields and motional properties for this state in AlN. Above 1100 K the mobile Mu + in AlN shows strong interactions and traps at another defect.