Electron effective mass and Si-donor binding energy in GaAs1-xNx probed by a high magnetic field

We study the magnetoresistance of the dilute nitride alloy GaAs1-xNx in magnetic fields up to 47 T. We observe a strong magnetophonon resonance effect and a large transverse magnetoresistance, which provide the means of measuring the N- induced enhancement of the electron effective mass and of investigating the magnetic freeze- out of conduction electrons on Si donors in GaAs1-xNx.