DISTINCT EXCITON-POLARON RESONANCE IN THE INFRARED EDGE EMISSION OF SEMIMAGNETIC HG1-XMNXTE

Results of a study of the 10-mu-m wavelength edge emission from narrow -gap Hg1-xMnxTe in magnetic fields are presented. Under moderate magne tic fields (B = 1.0-2.5 T) a strong resonance enhancement of the emiss ion and a narrowing of the linewidth to less than 2 meV, smaller than we are aware has been reported for spontaneous emission from a narrow- gap material, were observed. These observations were interpreted based on a theoretical model suggested by Karpov and Tsidil'kovskii in whic h the appearance of small gaps within the tails of the density of elec tron states in diluted magnetic semiconductors due to magnetic polaron formation is predicted. The observed resonance, based on this model, is tentatively interpreted as the coincidence between the energetic po sitions of this gap and the free-exciton line position, which is widel y tunable by applying a magnetic field in narrow-gap materials. This i s experimental evidence for the formation of a free exciton-polaron co mplex and the influence of excitonic effects in narrow-gap materials.