Abstract
The quantum Hall effect arises from the cyclotron motion of charge carriers in two-dimensional systems. However, the ground states related to the integer and fractional quantum Hall effect, respectively, are of entirely different origin1,2,3,4,5. The former can be explained within a single-particle picture; the latter arises from electron correlation effects governed by Coulomb interaction. The prerequisite for the observation of these effects is extremely smooth interfaces of the thin film layers to which the charge carriers are confined. So far, experimental observations of such quantum transport phenomena have been limited to a few material systems based on silicon, III–V compounds and graphene1,2,3,4,5,6,7,8,9. In ionic materials, the correlation between electrons is expected to be more pronounced than in the conventional heterostructures, owing to a large effective mass of charge carriers. Here we report the observation of the fractional quantum Hall effect in MgZnO/ZnO heterostructures grown by molecular-beam epitaxy, in which the electron mobility exceeds 180,000 cm2 V−1 s−1. Fractional states such as ν=4/3, 5/3 and 8/3 clearly emerge, and the appearance of the ν=2/5 state is indicated. The present study represents a technological advance in oxide electronics that provides opportunities to explore strongly correlated phenomena in quantum transport of dilute carriers.
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References
v. Klitzing, K., Dorda, G. & Pepper, M. New method for high-accuracy determination of the fine-structure constant based on quantized Hall resistance. Phys. Rev. Lett. 45, 494–497 (1980).
Tsui, D. C., Stormer, H. L. & Gossard, A. C. Two-dimensional magnetotransport in the extreme quantum limit. Phys. Rev. Lett. 48, 1559–1562 (1982).
Willett, R. et al. Observation of an even-denominator quantum number in the fractional quantum Hall effect. Phys. Rev. Lett. 59, 1776–1779 (1987).
Das Sarma, S. & Pinczuk, A. Perspectives in Quantum Hall Effects (Wiley-VCH, 1997).
Manfra, M. J., Pfeiffer, L. N., West, K. W., de Picciotto, R. & Baldwin, K. W. High mobility two-dimensional hole system in GaAs/AlGaAs quantum wells grown on (100) GaAs substrates. Appl. Phys. Lett. 86, 162106 (2005).
Nelson, S. F. et al. Observation of the fractional quantum Hall effect in Si/SiGe heterostructures. Appl. Phys. Lett. 61, 64–66 (1992).
De Poortere, E. P. et al. Enhanced electron mobility and high order fractional quantum Hall states in AlAs quantum wells. Appl. Phys. Lett. 80, 1583–1585 (2002).
Du, X., Skachko, I., Duerr, F., Luican, A. & Andrei, E. Y. Fractional quantum Hall effect and insulating phase of Dirac electrons in graphene. Nature 462, 192–195 (2009).
Bolotin, K. I., Ghahari, F., Shulman, M. D., Stormer, H. L. & Kim, P. Observation of the fractional quantum Hall effect in graphene. Nature 462, 196–199 (2009).
Ohtomo, A. & Hwang, H. Y. A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface. Nature 427, 423–426 (2004).
Tsukazaki, A. et al. Quantum Hall effect in polar oxide heterostructures. Science 315, 1388–1391 (2007).
Caviglia, A. D. et al. Electric field control of the LaAlO3/SrTiO3 interface ground state. Nature 456, 624–627 (2008).
Son, J. et al. Epitaxial SrTiO3 films with electron mobilities exceeding 30,000 cm2 V−1 s−1. Nature Mater. 9, 482–484 (2010).
Tsukazaki, A. et al. Spin susceptibility and effective mass of two-dimensional electrons in MgxZn1−xO/ZnO heterostructures. Phys. Rev. B 78, 233308 (2008).
Pfeiffer, L., West, K. W., Stormer, H. L. & Baldwin, K. W. Electron mobilities exceeding 107 cm2/Vs in modulation-doped GaAs. Appl. Phys. Lett. 55, 1888–1890 (1989).
Sajoto, T., Suen, Y. W., Engel, L. W., Santos, M. B. & Shayegan, M. Fractional quantum Hall effect in very-low-density GaAs/AlxGa1−xAs heterostructures. Phys. Rev. B 41, 8449–8460 (1990).
Umansky, V. et al. MBE growth of ultra-low disorder 2DEG with mobility exceeding 35×106 cm2/Vs. J. Cryst. Growth 311, 1658–1661 (2009).
Manfra, M. J. et al. Electron mobility exceeding 160000 cm2/Vs in AlGaN/GaN heterostructures grown by molecular-beam epitaxy. Appl. Phys. Lett. 85, 5394–5396 (2004).
Manfra, M. J. et al. Transport and percolation in a low-density high-mobility two-dimensional hole system. Phys. Rev. Lett. 99, 236402 (2007).
Du, R. R., Stormer, H. L., Tsui, D. C., Pfeiffer, L. N. & West, K. W. Experimental evidence for new particles in the fractional quantum Hall effect. Phys. Rev. Lett. 70, 2944–2947 (1993).
Boebinger, G. S. et al. Activation energies and localization in the fractional quantum Hall effect. Phys. Rev. B 36, 7919–7929 (1987).
Willett, R. L., Stormer, H. L., Tsui, D. C., Gossard, A. C. & English, J. H. Quantitative experimental test for the theoretical gap energies in the fractional quantum Hall effect. Phys. Rev. B 37, 8476–8479 (1988).
Lai, K., Pan, W., Tsui, D. C. & Xie, Y-H. Fractional quantum Hall effect at ν=2/3 and 4/3 in strained Si quantum wells. Phys. Rev. B 69, 125337 (2004).
Dean, C. R. et al. Intrinsic gap of the ν=5/2 fractional quantum Hall state. Phys. Rev. Lett. 100, 146803 (2008).
Pan, W. et al. Experimental studies of the fractional quantum Hall effect in the first excited Landau level. Phys. Rev. B 77, 075307 (2008).
Choi, H. C., Kang, W., Das Sarma, S., Pfeiffer, L. N. & West, K. W. Activation gaps of fractional quantum Hall effect in the second Landau level. Phys. Rev. B 77, 081301 (2008).
Ghosh, S. et al. Room-temperature spin coherence in ZnO. Appl. Phys. Lett. 86, 232507 (2005).
Baer, W. S. Faraday rotation in ZnO: Determination of the electron effective mass. Phys. Rev. 154, 785–789 (1967).
Acknowledgements
We wish to thank H. Aoki and D. Chiba for fruitful discussions and T. Kita for experimental help. A.T. is supported by the Japan Society for the Promotion of Science (JSPS) through its ‘Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program).’ A.O. and M.K. are supported by the Asahi Glass Foundation.
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A.T., A.O. and M.K. designed this research; A.T. carried out the experiments; A.T. and D.M. analysed the data; S.A. and K.N. fabricated the sample; Y.O. and H.O. contributed to the experimental set-up; and all authors co-wrote the manuscript.
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Tsukazaki, A., Akasaka, S., Nakahara, K. et al. Observation of the fractional quantum Hall effect in an oxide. Nature Mater 9, 889–893 (2010). https://doi.org/10.1038/nmat2874
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DOI: https://doi.org/10.1038/nmat2874
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