Regensburg 2019 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 35: HL Poster II
HL 35.27: Poster
Wednesday, April 3, 2019, 17:30–20:00, Poster E
Optical and magnetic studies of CrSe thin films on ZnSe and CdSe buffer layers — •Johannes Röder1, Dana Vieweg2, Hans-Albrecht Krug von Nidda2, Alois Loidl2, and Wolfram Heimbrodt1 — 1Department of Physics and Material Science Center, Philipps University, Marburg, Germany — 2Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, Germany
Theoretical calculations predicted Chromium chalcogenides in the zinc blende (ZB) structure to be promising candidates for half-metallic spin-aligner at room temperature. The thermodynamically stable phase of CrSe is the hexagonal NiAs-structure which exhibits antiferromagnetic behaviour.
We investigated and compared two different approaches to stabilize the ZB state of CrSe. CrSe layers have been grown by MBE either on a ZB-CdSe buffer on InAs substrate or on a ZB-ZnSe buffer on GaAs substrate. To study the magnetic phase transitions we did temperature dependent SQUID measurements. We observed ferromagnetic behaviour for the sample on ZnSe but anti-ferromagnetic behaviour for the sample grown on CdSe.
Furthermore, we did cw- as well as time resolved optical spectroscopic measurements. We were able to observe different excitonic transitions from the CrSe as well as from the ZnSe or CdSe layers. Of special interest was a spatially indirect transition in the CrSe/ZnSe heterostructure with the holes in ZnSe and the electrons in CrSe. The lifetimes and the polarization propertuies will be discussed in detail.