Molecular beam epitaxy of hexagonal Mn3Ge and its transport properties*

The chiral antiferromagnet Mn₃Ge is believed to be a Weyl semimetal and is a promising candidate for realizing tunable topological properties with applications in antiferromagnetic spintronics, especially in thin films and heterostructures. We will present recent work on synthesizing Mn₃Ge by molecular beam epitaxy (MBE). Without using any conducting buffer layer, c-axis oriented Mn₃Ge film can be epitaxially grown on LaAlO­₃ (111) _­with atomically smooth surfaces as indicated by in-situ reflection high energy electron diffraction (RHEED). These films can serve as model systems for studies of the surface states and interfacial properties. While the magnetization of our films is vanishingly small, a large anomalous Nernst signal has been observed. By rotating the antiferromagnetic structure in plane, the position of Weyl nodes can be varied in reciprocal space. We will present results on the angular dependence of both anisotropic magnetoresistance and anomalous Nernst effects, and generating spin-orbit torque using Mn₃Ge to source spin currents in heterostructures with magnetic overlayers.