Coherent {001} interfaces between rocksalt and zinc-blende crystal structures

Abstract

We study coherent, two-dimensional (2D) rocksalt PbTe epilayers in a zinc-blende CdTe matrix. The embedded material transforms during an annealing step into highly symmetric quantum dots with coherent interfaces. The atomic structure of the polar {001} interfaces between the two tellurides is investigated by high-resolution transmission electron microscopy in combination with multislice simulations. Both the original 2D PbTe epilayers and the resulting PbTe quantum dots are terminated by distinctively different cation-terminated [(001)A] and anion-terminated [(001)B] interfaces at opposite faces, whereas for the structurally similar ErAs/InGaAs heterosystem as yet only the (001)A interface was reported in the literature. Ab initio simulations were performed to assess these seeming differences, which were found to be mainly caused by the different polar bonding character of the involved II-VI and III-V compounds.