Reflection from an interface

A slight mismatch of left and right derivatives at the junction of a semi-infinite potential step is shown to cause dramatic changes in above-the-step reflectivity as a function of incident energy. Firstly, the reflectivity becomes enhanced remarkably at energies much above the step. Secondly, depending on the parameters, there exists a pronounced single minimum in the reflectivity at an energy slightly above-the-step height. Several methods and interfacial profiles have been employed to verify the claimed behaviour of the reflectivity.