Band Coupling Model of Electron and Hole Mediated Ferromagnetism in Semiconductors: The Case of GaN
Transition metal (TM) doped diluted magnetic semiconductors (DMSs) have many unique physical properties that can be used for magneto-optical and spintronic applications. The DMSs exhibit a wide range of magnetic ordering behavior. For example, Mn doped GaN can be either ferromagnetic or antiferromagnetic, depending on the Mn concentration, carrier density, or pressure. A unified band coupling model based on the p-d and d-d level repulsions between the TM and host elements are developed to explain the hole-induced ferromagnetism. We show that kinetic s-d coupling can be introduced through chemical ordering and strain, thus leading to electron-mediated ferromagnetism. Moreover, by using rare-earth elements (e.g., Gd) as magnetic dopants, the symmetry-allowed s-f coupling can also lead to a large splitting at the conduction band edge, producing electron-mediated ferromagnetism. Our model, therefore, provides a simple guideline for future band structure engineering of magnetic semiconductors.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC36-99GO10337
- OSTI ID:
- 940608
- Journal Information:
- Gallium Nitride Materials and Devices III: Proceedings of the SPIE Photonics West Conference, 21 January 2008, San Jose, California, Journal Name: Gallium Nitride Materials and Devices III: Proceedings of the SPIE Photonics West Conference, 21 January 2008, San Jose, California Vol. 6894
- Publisher:
- Bellingham, WA: SPIE - The International Society for Optical Engineering
- Country of Publication:
- United States
- Language:
- English
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