Comment on "Position-dependent effective masses in semiconductor theory"

Abstract
In a recent paper, von Roos criticized the concept of a position-dependent mass in semiconductor theory. His remarks are analyzed. It is shown that the Wannier Hamiltonian in the non-effective-mass approximation as devised by the authors is unique. The concept of position-dependent effective mass is a classical concept which in its classical form is unique and very useful for semiconductor device analysis.