DPG Phi
Verhandlungen
Verhandlungen
DPG

Berlin 2005 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

HL: Halbleiterphysik

HL 29: Spintronik IV

HL 29.1: Talk

Saturday, March 5, 2005, 15:00–15:15, TU P270

Preferred sites and valence states of transition metals in spintronic ZnGeP2 — •Wolfgang Gehlhoff1, Dmitri Azamat1, Axel Hoffmann1, and Nikolaus Dietz21Institute for Solid State Physics, Technical University Berlin, Germany — 2Department of Physics and Astronomy, Georgia State University, Atlanta, USA

The quest for room-temperature ferromagnetic semiconductors resulted in a recent interest in transition metal (TM) doped ternary pnictides AIIMIVX2V. The site preference and valence states for the different TM and their interaction with native defects play an important role in the discussion of the origin of the ferromagnetism [1, 2]. However, there are only few experimental data for the ternary pnictides [3]. For low Mn-doped samples the characteristic Mn2+ EPR spectra for isolated Mn2+ on group II site are observed. In higher doped ZnGeP2 we observed the formation of Mn-Mn pairs. In addition, we could detect new TM defects in unintentionally doped ZnGeP2.Without illumination of the samples we observed two iron-related spectra. The first one is identified as the spectrum of Fe2+ (3d6) incorporated on the Zn site with S=2 and a large zero-field splitting. The second one arises from Fe3+ (3d5) with S=5/2 and substitute for Ge site. Under illumination we observed the spectrum from Fe+ on Zn site. The strongest Cr-related spectrum is caused by Cr4+ on Ge site.
P. Mahadevan and A. Zunger, Phys. Rev. Lett. 88, 047205 (2002)
T. Kamatani and H. Akai, Phase Transitions 76, 401 (2003)
W. Gehlhoff, D. Azamat, A. Hoffmann, Materials Science in Semiconductor Processing, Vol.6 (2003) pp. 379-383

100% | Mobile Layout | Deutsche Version | Contact/Imprint/Privacy
DPG-Physik > DPG-Verhandlungen > 2005 > Berlin