Evidence of two disorder scales in Ga(AsBi)

Temperature-dependent photoluminescence in a Ga(AsBi) structure is modelled in an excitonic hopping model and compared to experiment. It is shown that theory and experiment cannot be brought into agreement when using a single energy scale. Thus, a second energy scale is introduced, resulting in a good agreement between theory and experiment. The two scales are identified with spatially large alloy disorder and additional cluster states subdividing this first scale.