Electron mass in dilute nitrides and its anomalous dependence on hydrostatic pressure

The dependence of the electron mass on hydrostatic pressure P in N-diluted GaAs(1-x)N(x) (x=0.10% and 0.21%) is investigated by magnetophotoluminescence. Exceedingly large fluctuations (up to 60%/kbar) in the electron mass with increasing P are found. These originate from a pressure-driven tuning of the hybridization degree between the conduction band minimum and specific nitrogen-related states. Present results suggest a hierarchy between different nitrogen complexes as regards the extent of the perturbation these complexes exert on the electronic properties of the GaAs host.