Optical transitions in broken gap heterostructures

We have used an eight-band model to investigate the electronic structures a nd to calculate the optical matrix elements of InAs-GaSb broken gap semicon ductor heterostructures. The unusual hybridization of the conduction band s tates in the InAs layers with the valence band states in the GaSb layers ha s been analyzed in detail. We have studied the dependence of the optical ma trix elements on the degree of conduction-valence hybridization, the tuning of the hybridization by varying the width of the GaSb layers and/or InAs l ayers, and the sensitivity of quantized levels to this tuning. Large spin-o rbit splitting in the energy bands has been demonstrated. Our calculation c an serve as a theoretical model for infrared lasers based on broken gap qua ntum well heterostructures.