Abstract: A modified LLP variational method is adopted to discuss the polaronic effect on the binding energy of an impurity in an infinite quantum well by considering the pressure and screening effects.The influences from three optical phonon modes in the system (including confined longitudinal optical (LO) phonons,half-space LO phonons,and interface optical phonons) on the binding energy are considered.The results show that the polaronic effect significantly decreases the binding energy,but pressure weakens the polaronic effect.The influence of screening on the polaronic effect is not apparent.

Key words: quantum well, screening, pressure, impurity state, binding energy, polaronic effect