Optical And Magnetic Characterization Of ZnSe/MnSe Superlattices

Abstract

One of the more striking recent illustrations of the versatility of molecular beam epitaxial methods (MBE) in preparing II-VI compound semiconductor superlattices (SL) is the synthesis of ZnSe/MnSe structures where the wide gap magnetic semiconductor MnSe is available for study in zincblende form for the first time. Of basic interest in these strained layer superlattices are electronic and magnetic phenomena near the two-dimensional (2D) limit. From another perspective, spectroscopic studies in the limit of ultrathin layer structures can provide valuable information about the details of MBE growth, particularly on the nature of the heterointerfaces. A particular advantage is present in a semiconductor such as MnSe because of its magnetic properties which are inherently sensitive to short range atomic ordering on the scale of the chemical bondlength. In this paper we review recent results based on optical spectroscopy and direct magnetization measurements which show dramatic departures from bulk behavior in their magnetic signature when m individual MnSe layers approach the onolayer limit. These results strongly suggest the presence of microscopic reconstruction effects at the MnSe/ZnSe heterointerfaces which appear to be quite efficient in frustrating antiferromagnetic ordering in these superlattices.