Exciton spin splitting in ultrathin InAs layers

Unique spin splitting behaviors in ultrathin InAs layers, which show very different spin splitting characteristics between the InAs monolayer (ML) and submonolayer (SML) have been observed. While distinct spin splitting is observed in an InAs ML, no visible spin splitting is found in a 1/3 ML InAs SML. In addition, the spin relaxation time in the 1/3 ML InAs is found to be much longer than that in the 1 ML sample. These results are in good agreement with the theoretical prediction that the interexcitonic exchange interaction plays a dominant role in energy splitting, while the intraexciton exchange interaction controls the spin relaxation. (c) 2007 American Institute of Physics.