The epitaxial growth behavior of thin PbMnTe film on BaF2(1 1 1): Influence of Mn doping density and substrate temperatures

Abstract

PbMnTe film attracted intense scientific attention because of its promising properties such as enhanced magneto-optical effects, huge negative magneto-resistance effect, and Curie-Weiss paramagnetism. The electro-magnetic properties of PbMnTe film were intensively studied in the past decades. In contrast, the fabrication of PbMnTe film was still less investigated and its growth behavior was needed to be better understood. In this work, we study the growth behaviors of Pb1−xMnxTe as a function of Mn content (x) and temperatures of BaF2(111) substrate. The structure and growth behavior of Pb1−xMnxTe film changed substantially when the Mn content is larger than the criteria of x = 0.026. Mn will replace the position of Pb2+ for cases of x <0.026, leading to the formation of (111)-orientated NaCl-type Pb1−xMnxTe spirals. In contrast, MnTe phase segregated from the Pb1−xMnxTe phase and aggregates at positions of the threading dislocations for cases of x >0.026, resulting in the formation of pit-like domains on the spiral islands of PbMnTe alloy film. The pit-like MnTe grains aggregated nearby the threading dislocations due to the existence of the stress field at these defect regions. The criteria of Mn to replace Pb increases when deposited PbMnTe at higher substrate temperature. This indicates that the quality of Pb1−xMnxTe film would be improved if the substrate was kept at high temperature while in deposition.