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Precise tuning of the Curie temperature of (Ga,Mn)As-based magnetic semiconductors by hole compensation: Support for valence-band ferromagnetism

Zhou, Shengqiang; Li, Lin; Yuan, Ye; Rushforth, A.W.; Chen, Lin; Wang, Yutian; Böttger, R.; Heller, R.; Zhao, Jianhua; Edmonds, K.W.; Campion, R.P.; Gallagher, B.L.; Timm, C.; Helm, M.

Authors

Shengqiang Zhou

Lin Li

Ye Yuan

A.W. Rushforth Andrew.Rushforth@nottingham.ac.uk

Lin Chen

Yutian Wang

R. Böttger

R. Heller

Jianhua Zhao

K.W. Edmonds

R.P. Campion

B.L. Gallagher

C. Timm

M. Helm



Abstract

For the prototype diluted ferromagnetic semiconductor (Ga,Mn)As, there is a fundamental concern about the electronic states near the Fermi level, i.e., whether the Fermi level resides in a well-separated impurity band derived from Mn doping (impurity-band model) or in the valence band that is already merged with the Mn-derived impurity band (valence-band model). We investigate this question by carefully shifting the Fermi level by means of carrier compensation. We use helium-ion implantation, a standard industry technology, to precisely compensate the hole doping of GaAs-based diluted ferromagnetic semiconductors while keeping the Mn concentration constant. We monitor the change of Curie temperature (TC) and conductivity. For a broad range of samples including (Ga,Mn)As and (Ga,Mn)(As,P) with various Mn and P concentrations, we observe a smooth decrease of TC with carrier compensation over a wide temperature range while the conduction is changed from metallic to insulating. The existence of TC below 10 K is also confirmed in heavily compensated samples. Our experimental results are naturally explained within the valence-band picture.

Journal Article Type Article
Publication Date Aug 15, 2016
Journal Physical Review B
Print ISSN 2469-9950
Electronic ISSN 2469-9969
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 94
Issue 7
APA6 Citation Zhou, S., Li, L., Yuan, Y., Rushforth, A., Chen, L., Wang, Y., …Helm, M. (2016). Precise tuning of the Curie temperature of (Ga,Mn)As-based magnetic semiconductors by hole compensation: Support for valence-band ferromagnetism. Physical Review B, 94(7), https://doi.org/10.1103/PhysRevB.94.075205
DOI https://doi.org/10.1103/PhysRevB.94.075205
Publisher URL http://journals.aps.org/prb/abstract/10.1103/PhysRevB.94.075205
Copyright Statement Copyright information regarding this work can be found at the following address: http://eprints.nottingh.../end_user_agreement.pdf
Additional Information Shengqiang Zhou, Lin Li, Ye Yuan, A. W. Rushforth, Lin Chen, Yutian Wang, R. Böttger, R. Heller, Jianhua Zhao, K. W. Edmonds, R. P. Campion, B. L. Gallagher, C. Timm, and M. Helm Phys. Rev. B 94, 075205 – Published 15 August 2016

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Copyright Statement
Copyright information regarding this work can be found at the following address: http://eprints.nottingham.ac.uk/end_user_agreement.pdf





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