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MA: Fachverband Magnetismus
MA 52: Poster II
MA 52.55: Poster
Thursday, March 15, 2018, 15:00–18:00, Poster C
MBE growth of I-Mn-V antiferromagnets — •Martin Brajer1,2, Štěpán Svoboda1, Richard Campion3, and Vít Novák1 — 1Institute of Physics ASCR, v.v.i., Cukrovarnicka 10, 162 53 Praha, Czech Republic — 2Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, 121 16 Prague, Czech Republic — 3School of Physics and Astronomy, University of Nottingham, UK
We report on growth of two members of the I-Mn-V family of room-temperature antiferromagnets (AFs) by means of molecular beam epitaxy: tetragonal phase CuMnAs and LiMnAs. The former is an AF semimetal with broken inversion symmetry, allowing for current-induced switching of AF moments. It can be successfully grown on standard zinc-blende semiconductor substrates GaAs, GaP and Si. We study strain relaxation and surface morphology of the material depending on the type of the substrate used. The latter is tetragonal LiMnAs, an AF semiconductor with band-gap of 1.6 eV. It can be grown on a lattice-matched InAs substrate, which allows for a stable 2D growth, but hinders its basic transport characterization because of the high substrate conductivity. We attempt to overcome this problem by using a thin metamorphic (Ga,In)As layer on top of an insulating GaAs substrate. This approach brings about a problem of strain relaxation and related surface morphology degradation: the thinner the metamorphic layer (i.e. the lower its conductance), the higher the density of misfit dislocations, calling for a compromise between the suppression of the parasitic conductivity and enhanced surface roughness.