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First principles studies of GeTe based dilute magnetic semiconductors
T Fukushima1, H Shinya, H Fujii
1Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|November 28, 2014
Summary
GeTe-based dilute magnetic semiconductors (DMS) exhibit high transition metal solubility, enabling potential room-temperature ferromagnetism. Chromium and manganese doping, along with germanium vacancies, enhance ferromagnetic interactions for spintronics applications.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Semiconductor Physics
Background:
- Dilute magnetic semiconductors (DMS) are crucial for spintronics.
- GeTe-based materials offer unique electronic properties.
- Understanding transition metal doping effects is key to developing advanced DMS.
Purpose of the Study:
- Investigate the electronic structure and magnetic properties of GeTe-based DMS.
- Determine the solubility and ferromagnetic potential of transition metal impurities in GeTe.
- Explore mechanisms for achieving room-temperature ferromagnetism in these materials.
Main Methods:
- Korringa-Kohn-Rastoker Green's function method.
- Projector augmented wave method.
- Monte Carlo simulation for classical Heisenberg model.
Main Results:
- High solubilities of transition metal impurities in GeTe were predicted.
- GeTe-based DMS show potential for room-temperature ferromagnetism.
- (Ge, Cr)Te exhibits strong ferromagnetic interaction via double exchange.
- Ge vacancies in (Ge, Mn)Te activate p-d exchange, leading to ferromagnetism.
Conclusions:
- GeTe-based DMS are promising for semiconductor spintronics.
- Doping strategies and defect engineering can control magnetic properties.
- Calculated exchange coupling constants and Curie temperatures support experimental findings.
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