Abstract
The ferromagnetic semiconductor (Ga,Mn)As has emerged as the most studied material for prototype applications in semiconductor spintronics. Because ferromagnetism in (Ga,Mn)As is hole-mediated, the nature of the hole states has direct and crucial bearing on its Curie temperature TC. It is vigorously debated, however, whether holes in (Ga,Mn)As reside in the valence band or in an impurity band. Here we combine results of channelling experiments, which measure the concentrations both of Mn ions and of holes relevant to the ferromagnetic order, with magnetization, transport, and magneto-optical data to address this issue. Taken together, these measurements provide strong evidence that it is the location of the Fermi level within the impurity band that determines TC through determining the degree of hole localization. This finding differs drastically from the often accepted view that TC is controlled by valence band holes, thus opening new avenues for achieving higher values of TC.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Dietl, T. A ten-year perspective on dilute magnetic semiconductors and oxides. Nature Mater. 9, 965–974 (2010).
Dietl, T., Ohno, H., Matsukura, F., Cibert, J. & Ferrand, D. Zener model description of ferromagnetism in zinc-blende magnetic semiconductors. Science 287, 1019–1022 (2000).
Jungwirth, T. et al. Character of states near the Fermi level in (Ga,Mn)As: Impurity to valence band crossover. Phys. Rev. B 76, 125206 (2007).
Sawicki, M. Magnetic properties of (Ga,Mn)As. J. Magn. Magn. Mater. 300, 1–6 (2006).
Neumaier, D. et al. All-electrical measurements of the density of states in (Ga,Mn)As. Phys. Rev. Lett. 103, 087203 (2009).
Sawicki, M. et al. Experimental probing of the interplay between ferromagnetism and localization in (Ga,Mn)As. Nature Phys. 6, 22–25 (2010).
Richardella, A. et al. Visualizing critical correlations near the metal–insulator transition in Ga1−xMnxAs. Science 327, 665–669 (2010).
Boukari, H. et al. Light and electric field control of ferromagnetism in magnetic quantum structures. Phys. Rev. Lett. 88, 207204 (2002).
Jungwirth, T., König, J., Sinova, J., Kučera, J. & MacDonald, A. H. Curie temperature trends in (III, Mn)V ferromagnetic semiconductors. Phys. Rev. B 66, 012402 (2002).
Nishitani, Y. et al. Curie temperature versus hole concentration in field-effect structures of Ga1−xMnxAs. Phys. Rev. B 81, 045208 (2010).
Wang, K. Y. et al. Influence of the Mn interstitial on the magnetic and transport properties of (Ga,Mn)As. J. Appl. Phys. 95, 6512–6514 (2004).
Ku, K. C. et al. Highly enhanced Curie temperature in low-temperature annealed [Ga,Mn]As epilayers. Appl. Phys. Lett. 82, 2302–2304 (2003).
Sato, K., Dederichs, P. H. & Katayama-Yoshida, H. Curie temperatures of III–V diluted magnetic semiconductors calculated from first principles. Europhys. Lett. 61, 403–408 (2003).
Berciu, M. & Bhatt, R. N. Effects of disorder on ferromagnetism in diluted magnetic semiconductors. Phys. Rev. Lett. 87, 107203 (2001).
Mahadevan, P. & Zunger, A. Trends in ferromagnetism, hole localization, and acceptor level depth for Mn substitution in GaN, GaP, GaAs, GaSb. Appl. Phys. Lett. 85, 2860–2862 (2004).
Erwin, S. C. & Petukhov, A. G. Self-compensation in Manganese-doped ferromagnetic semiconductors. Phys. Rev. Lett. 89, 227201 (2002).
Alberi, K. et al. Formation of Mn-derived impurity band in III-Mn-V alloys by valence band anticrossing. Phys. Rev. B 78, 075201 (2008).
Mayer, M. A. et al. Electronic structure of Ga1−xMnxAs analyzed according to hole-concentration-dependent measurements. Phys. Rev. B 81, 045205 (2010).
Burch, K., Awschalom, D. & Basov, D. Optical properties of III-Mn-V ferromagnetic semiconductors. J. Magn. Magn. Mater. 320, 3207–3228 (2008).
Burch, K. S. et al. Impurity band conduction in a high temperature ferromagnetic semiconductor. Phys. Rev. Lett. 97, 087208 (2006).
Rokhinson, L. P. et al. Weal localization in Ga1−xMnxAs: Evidence of impurity band transport. Phys. Rev. B 76, 161201 (2007).
Ohya, S., Muneta, I., Hai, P. N. & Tanaka, M. Valence-band structure of the ferromagnetic semiconductor (Ga,Mn)As studied by spin-dependent resonant tunneling spectroscopy. Phys. Rev. Lett. 104, 167204 (2010).
Sheu, B. L. et al. Onset of ferromagnetism in low-doped Ga1−xMnxAs. Phys. Rev. Lett. 99, 227205 (2007).
Tang, J-M. & Flatte, M. E. Magnetic circular dichroism from the impurity band in III–V diluted magnetic semiconductors. Phys. Rev. Lett. 101, 157203 (2008).
Ohya, S., Takata, K. & Tanaka, M. Nearly non-magnetic valence band of the ferromagnetic semiconductor (Ga,Mn)As. Nature Phys. 7, 342–347 (2011).
Chapler, B. C. et al. Infrared probe of the insulator-to-metal transition in Ga1−xMnxAs and Ga1−xBexAs. Phys. Rev. B 84, 081203 (2011).
Yu, K. M. et al. Effect of the location of Mn sites in ferromagnetic Ga1−xMnxAs on its Curie temperature. Phys. Rev. B 65, 201303 (2002).
Blinowski, J. & Kacman, P. Spin interactions of interstitial Mn ions in ferromagnetic (Ga,Mn)As. Phys. Rev. B 67, 121204 (2003).
Mašek, C. J. & Máca, F. Interstitial Mn in (Ga,Mn)As: Binding energy and exchange coupling. Phys. Rev. B 69, 165212 (2004).
Edmonds, K. W. et al. Mn Interstitial Diffusion in (Ga,Mn)As. Phys. Rev. Lett. 92, 037201 (2004).
Bouzerar, G., Ziman, T. & Kudrnovský, J. Compensation, interstitial defects, and ferromagnetism in diluted ferromagnetic semiconductors. Phys. Rev. B 72, 125207 (2005).
Takeda, Y. et al. Nature of magnetic coupling between Mn ions in As-Grown Ga1−xMnxAs studied by X-Ray magnetic circular dichroism. Phys. Rev. Lett. 100, 247202 (2008).
Jungwirth, T. et al. Prospects for high temperature ferromagnetism in (Ga,Mn)As semiconductors. Phys. Rev. B 72, 165204 (2005).
Yu, K. M. et al. Curie temperature limit in ferromagnetic Ga1−xMnxAs. Phys. Rev. B 68, 041308 (2003).
Wojtowicz, T., Furdyna, J. K., Liu, X., Yu, K. M. & Walukiewicz, W. Electronic effects determining the formation of ferromagnetic III1−xMnxV alloys during epitaxial growth. Physica E 25, 171–180 (2004).
MacDonald, A. H., Schiffer, P. & Samarth, N. Ferromagnetic semiconductors: Moving beyond (Ga,Mn)As. Nature Mater. 4, 195–202 (2005).
Yu, K. M. et al. in Fermi Level Effects on Mn Incorporation in III-Mn-V Ferromagnetic Semiconductors Vol. 82 (eds Dietl, T., Awchalom, D. D., Kamińska, M. & Ohno, H.) (Spintronics, Semiconductors and Semimetals, Elsevier, 2008).
Sadowski, J. et al. Structural and magnetic properties of (Ga,Mn)As layers with high Mn-content grown by migration-enhanced epitaxy on GaAs(100) substrates. Appl. Phys. Lett. 78, 3271–3273 (2001).
Wolos, A. et al. Properties of arsenic antisite defects in Ga1−xMnxAs. J. Appl. Phys. 96, 530–533 (2004).
Cho, Y. J., Yu, K. M., Liu, X., Walukiewicz, W. & Furdyna, J. K. Effects of donor doping on Ga1−xMnxAs. Appl. Phys. Lett. 93, 262505 (2008).
Berciu, M. et al. Origin of magnetic circular dichroism in (Ga,Mn)As: Giant Zeeman splitting vs. spin dependent density of states. Phys. Rev. Lett. 102, 247202 (2009).
Moca, C. P., Zarand, G. & Berciu, M. Theory of optical conductivity for dilute Ga1−xMnxAs. Phys. Rev. B 80, 165202 (2009).
Kirby, B. J. et al. Annealing-dependent magnetic depth profile in Ga1−xMnxAs. Phys. Rev. B 69, 081307 (2004).
Liu, X., Sasaki, Y. & Furdyna, J. K. Ferromagnetic resonance in Ga1−xMnxAs. Phys. Rev. B 67, 205204 (2003).
Acknowledgements
K.T. thanks Y-Y. Zhou for her help with the MCD set-up and sample preparation. This work was supported by the National Science Foundation Grant DMR 10-05851; by the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canadian Institute for Advanced Research (CIFAR) and by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, of the US Department of Energy under Contract No. DE — AC02-05CH11231.
Author information
Authors and Affiliations
Contributions
M.D. and M.B. conceived the project and wrote the manuscript. K.T. carried out the MCD, transport and magnetization experiments with guidance from X.L., M.D. and J.K.F. X.L. fabricated the samples and contributed to the manuscript. K.M.Y. and W.W. are responsible for the channelling experiments. The project was supervised by M.D. and J.K.F. All authors have reviewed, discussed and approved the results and conclusions of this article.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary Information
Supplementary Information (PDF 341 kb)
Rights and permissions
About this article
Cite this article
Dobrowolska, M., Tivakornsasithorn, K., Liu, X. et al. Controlling the Curie temperature in (Ga,Mn)As through location of the Fermi level within the impurity band. Nature Mater 11, 444–449 (2012). https://doi.org/10.1038/nmat3250
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nmat3250
This article is cited by
-
Theoretical Perspective of Fe-Induced Ferromagnetism in Antimonene: A Hybrid Functional Study
Journal of Electronic Materials (2024)
-
Small-voltage multiferroic control of two-dimensional magnetic insulators
Nature Electronics (2023)
-
Electron localization induced by intrinsic anion disorder in a transition metal oxynitride
Communications Physics (2021)
-
Ultrahigh-temperature ferromagnetism in MoS2 Moiré superlattice/graphene hybrid heterostructures
Nano Research (2021)
-
Site-specific spectroscopic measurement of spin and charge in (LuFeO3)m/(LuFe2O4)1 multiferroic superlattices
Nature Communications (2020)