Regensburg 2019 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 14: Poster
DS 14.43: Poster
Dienstag, 2. April 2019, 17:00–20:00, Poster E
Structural and electrical properties of layered FeGe2 thin films — •Samuel Gaucher, Bernd Jenichen, and Jens Herfort — Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany
The solid-phase epitaxy (SPE) of Ge thin films over Fe3Si surfaces was investigated recently as a solution to create lattice-matched heterojunctions. A persistent challenge in this field had been to grow epitaxial semiconductors over metals by MBE, a limiting factor for a number of envisaged applications in the field of spintronics. In order to solve this issue, amorphous Ge was deposited on ferromagnetic quasi-Heusler compound Fe3Si and crystallized slowly by annealing. Instead of pure Ge, the resulting single-crystalline films were shown to be a new 2D polymorph of FeGe2 with space group P4mm. TEM studies reveal a layered structure with monolayer Fe planes sitting between tetragonal Ge bilayers.1 The material does not exist in a bulk form, its creation being interpreted as an ordering phenomenon induced by minimization of the elastic energy of the epitaxial film.1 It is possible to isolate the material on an insulating GaAs substrate by first growing a few monolayers of crystalline Fe3Si, and then thicker amorphous Ge in a ratio such as to obtain the right stoichiometry for FeGe2 (with some Si atoms sitting on Ge sites). Electrical measurements conducted on FeGe2 films of 8 to 12 nm indicate a thickness dependence of their resistivity. Magnetotransport at low temperature reveal a strong anomalous Hall effect.
1Jenichen et al., Phys. Rev. Mater. 2, 051402 (2018).