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APS » Journals » Phys. Rev. Lett. » Volume 99 » Issue 22
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Phys. Rev. Lett. 99, 227205 (2007) [4 pages]

Onset of Ferromagnetism in Low-Doped Ga1-xMnxAs

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B. L. Sheu1, R. C. Myers2, J.-M. Tang3,*, N. Samarth1, D. D. Awschalom2, P. Schiffer1, and M. E. Flatté3
1Physics Department and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA
2Center for Spintronics and Quantum Computation, University of California, Santa Barbara, California 93106, USA
3Optical Science and Technology Center and Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA

Received 30 July 2007; published 28 November 2007

We develop a quantitatively predictive theory for impurity-band ferromagnetism in the low-doping regime of Ga1-xMnxAs. We compare it with measurements of a series of samples whose compositions span the transition from paramagnetic insulating to ferromagnetic conducting behavior. The theoretical Curie temperatures depend sensitively on the local fluctuations in the Mn-hole binding energy, which originate from Mn disorder and As antisite defects. The experimentally determined hopping energy is an excellent predictor of the Curie temperature, in agreement with the theory.

© 2007 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.99.227205
DOI:
10.1103/PhysRevLett.99.227205
PACS:
75.47.−m, 72.20.Ee, 75.30.Hx, 75.50.Pp

*Current address: Department of Physics, University of New Hampshire, Durham, NH 03824, USA.

 
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