Precise quantization of anomalous Hall effect near zero magnetic field

Journal Article · Mon May 04 04:00:00 EDT 2015 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.114.187201· OSTI ID:1177765

Bestwick, A. J. ^[1]; Fox, E. J. ^[1]; Kou, Xufeng ^[2]; Pan, Lei ^[2]; Wang, Kang L. ^[2]; Goldhaber-Gordon, D. ^[1]

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1. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
2. Univ. of California, Los Angeles, CA (United States)

In this study, we report a nearly ideal quantum anomalous Hall effect in a three-dimensional topological insulator thin film with ferromagnetic doping. Near zero applied magnetic field we measure exact quantization in the Hall resistance to within a part per 10,000 and a longitudinal resistivity under 1 Ω per square, with chiral edge transport explicitly confirmed by nonlocal measurements. Deviations from this behavior are found to be caused by thermally activated carriers, as indicated by an Arrhenius law temperature dependence. Using the deviations as a thermometer, we demonstrate an unexpected magnetocaloric effect and use it to reach near-perfect quantization by cooling the sample below the dilution refrigerator base temperature in a process approximating adiabatic demagnetization refrigeration.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 1177765
• Report Number(s): SLAC-PUB--16247; arXiv:1412.3189
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 18 Vol. 114; ISSN 0031-9007; ISSN PRLTAO
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

MATSCI