Bound states within the continuum — A metamaterial-semiconductor analogy

The existence of bound states within the continuum has been known since the early years of quantum mechanics. However a realistic quantum system supporting such bound states has not yet been designed. Here we present a core-shell semiconductor heterostructure composed of Hg_1-xCd_xTe compounds, which is able to support the bound states within the continuum using zero-valued effective mass within the outer shell. The working principle is analogous to that of the recently proposed open core-shell plasmonic resonators for light waves.