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Nat Mater. 2015 May;14(5):473-7. doi: 10.1038/nmat4204. Epub 2015 Mar 2.

High-precision realization of robust quantum anomalous Hall state in a hard ferromagnetic topological insulator.

Author information

1
Francis Bitter Magnet Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
2
The Center for Nanoscale Science and Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802-6300, USA.
3
Department of Physics, Stanford University, Stanford, California 94305-4045, USA.
4
Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA.
5
1] Francis Bitter Magnet Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA [2] Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

Abstract

The discovery of the quantum Hall (QH) effect led to the realization of a topological electronic state with dissipationless currents circulating in one direction along the edge of a two-dimensional electron layer under a strong magnetic field. The quantum anomalous Hall (QAH) effect shares a similar physical phenomenon to that of the QH effect, whereas its physical origin relies on the intrinsic spin-orbit coupling and ferromagnetism. Here, we report the experimental observation of the QAH state in V-doped (Bi,Sb)2Te3 films with the zero-field longitudinal resistance down to 0.00013 ± 0.00007h/e(2) (~3.35 ± 1.76 Ω), Hall conductance reaching 0.9998 ± 0.0006e(2)/h and the Hall angle becoming as high as 89.993° ± 0.004° at T = 25 mK. A further advantage of this system comes from the fact that it is a hard ferromagnet with a large coercive field (Hc > 1.0 T) and a relative high Curie temperature. This realization of a robust QAH state in hard ferromagnetic topological insulators (FMTIs) is a major step towards dissipationless electronic applications in the absence of external fields.

PMID:
25730394
DOI:
10.1038/nmat4204

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