Motionally Dependent Bound States in Semiconductor Quantum Wells

With a simple model it is demonstrated that semiconductor quantum wells can exhibit motionally dependent binding. The dependence of binding on transverse motion results from mass mismatch at the quantum-well interfaces and can occur in both parabolic and nonparabolic systems. Accumulation layers on degenerate semiconductors such as $n-\mathrm{InAs}$ are shown to provide observational evidence for the effect. Implications for quantum-well experiments and applications are discussed.