Interface States in Subband Structure of Semiconductor Quantum Wells

An analytical investigation is made of semiconductor quantum‐well subband structures using the three‐band Kane model. The analysis is based on the assumption, that electron and light hole masses are much smaller than heavy hole mass in the heterostructure. It is demonstrated, that some anomalies in the subband spectrum are due to the interaction with interface states, others are generated by the repulsion between the subbands near the points of their quasiintersections. For the heterostructure, composed of the gapless layer in a finite‐gap bulk material, the interface state is found to cause a nonmonotonous dependence of the gap on the layer thickness.