Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 44: Poster Session I

HL 44.1: Poster

Dienstag, 15. März 2011, 18:00–21:00, P3

Antiferromagnetic semiconductor LiMnAs — Vit Novak¹, Tomas Jungwirth¹, Miroslav Cukr¹, •Stepan Svoboda^1,2, Zbynek Soban^1,3, Xavier Marti², Vaclav Holy², Petra Horodyska², and Petr Nemec² — ¹Institute of Physics AS CR, Cukrovarnicka 10, Praha, Czech Republic — ²Charles University, Ke Karlovu 5, Praha, Czech Republic — ³Czech Technical University, Technicka 2, Praha, Czech Republic

LiMnAs belongs to the theoretically predicted class of I-Mn-V semiconductors with the antiferromagnetic ordering of Mn atoms. We report its first successful preparation in form of a thin film by molecular beam epitaxy. Structural properties of the material were examined in-situ by RHEED, and ex-situ by XPS and XRD, confirming the tetragonal crystal structure with its [100] direction oriented along the [110] direction of the InAs substrate. Transparency of LiMnAs in the spectral range of 870 to 1400 nm confirms the existence of an optical gap and indicates the band-gap energy above 1.4 eV. Magnetic properties measured by SQUID magnetometry show nearly compensated net magnetic moment in temperatures up to 400 K and magnetic fields up to 7 T, in a clear contrast to the ferromagnetic character of MnAs or to the paramagnetic behavior of the same amount of uncoupled Mn atoms.