CuMn-V compounds: a transition from semimetal low-temperature to semiconductor high-temperature antiferromagnets

摘要

We report on a theoretical and experimental study of CuMn-V antiferromagnets.Previous works showed low-temperature antiferomagnetism and semimetalelectronic structure of the semi-Heusler CuMnSb. In this paper we presenttheoretical predictions of high-temperature antiferromagnetism in the stableorthorhombic phases of CuMnAs and CuMnP. The electronic structure of CuMnAs isat the transition from a semimetal to a semiconductor and we predict that CuMnPis a semiconductor. We show that the transition to a semiconductor-like bandstructure upon introducing the lighter group-V elements is present in both themetastable semi-Heusler and the stable orthorhombic crystal structures. On theother hand, the orthorhombic phase is crucial for the high N\'eel temperature.Results of X-ray diffraction, magnetization, transport, and neutron diffractionmeasurements we performed on chemically synthesized CuMnAs are consistent withthe theory predictions.