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Orthogonal magnetization and symmetry breaking in pyrochlore iridate Eu2Ir2O7

Nature Physics volume 13, pages 599–603 (2017)Cite this article

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Abstract

Electrons in the pyrochlore iridates experience a large interaction energy in addition to a strong spin–orbit interaction. Both features make the iridates promising for realizing novel states such as the topological Mott insulator. The pyrochlore iridate Eu2Ir2O7 shows a metal–insulator transition at TN ∼ 120 K below which a magnetically ordered state develops. Using torque magnetometry, we uncover an unusual magnetic response. A magnetic field H applied in its a–b plane produces a nonlinear magnetization M⊥ orthogonal to the plane. M⊥ displays a d-wave field-angle pattern consistent with octupolar order, with a handedness dictated by field cooling, leading to symmetry breaking of the chirality ω. A surprise is that the lobe orientation of the d-wave pattern is sensitive to the direction of the field when the sample is field-cooled below TN, suggestive of an additional order parameter η already present at 300 K.

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Figure 1: Pyrochlore lattice, orientation of the lab axes, and analysis of the torque signal.
Figure 2: Angular variation of τ⊥ ≡ M⊥Hcosφ and the effect of Hfc on the d-wave orientation of M⊥.
Figure 3: Hysteretic behaviour and T dependence of the orthogonal magnetization M⊥.
Figure 4: Paramagnetic magnetization.

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References

  1. Pesin, D. & Balents, L. Mott physics and band topology in materials with strong spin–orbit interaction. Nat. Phys. 6, 376–381 (2010).

    Article  Google Scholar 

  2. Jackeli, G. & Khaliullin, G. Mott insulators in the strong spin–orbit coupling limit: from Heisenberg to a quantum compass and Kitaev models. Phys. Rev. Lett. 102, 017205 (2009).

    Article  ADS  Google Scholar 

  3. Witczak-Krempa, W., Chen, G., Kim, Y. B. & Balents, L. Correlated quantum phenomena in the strong spin-orbit regime. Annu. Rev. Condens. Matter Phys. 5, 57–82 (2014).

    Article  ADS  Google Scholar 

  4. Wan, X., Turner, A. M., Vishwanath, A. & Savrasov, S. Y. Topological semimetal and Fermi-arc surface states in the electronic structure of pyrochlore iridates. Phys. Rev. B 83, 205101 (2011).

    Article  ADS  Google Scholar 

  5. Turner, A. M. & Vishwanath, A. in Topological Insulators Vol. 6 (eds Franz, M. & Molenkamp, L.) Ch. 11, 293–324 (Elsevier, 2013).

    Book  Google Scholar 

  6. Witczak-Krempa, W., Chen, G., Kim, Y. B. & Balents, L. Correlated quantum phenomena in the strong spin-orbit regime. Annu. Rev. Condens. 5, 57–82 (2014).

    Article  Google Scholar 

  7. Witczak-Krempa, W. & Kim, Y. B. Topological and magnetic phases of interacting electrons in the pyrochlore iridates. Phys. Rev. B 85, 045124 (2012).

    Article  ADS  Google Scholar 

  8. Savary, L., Moon, E.-G. & Balents, L. New type of quantum criticality in the pyrochlore iridates. Phys. Rev. X 4, 041027 (2014).

    Google Scholar 

  9. Kim, B. J. et al. Novel Jeff = 1/2 Mott state induced by relativistic spin-orbit coupling in Sr2IrO4 . Phys. Rev. Lett. 101, 076402 (2008).

    Article  ADS  Google Scholar 

  10. Kim, B. J. et al. Phase-sensitive observation of a spin-orbital Mott state in Sr2IrO4 . Science 323, 1329–1332 (2009).

    Article  ADS  Google Scholar 

  11. Matsuhira, K. et al. Metal-insulator transition in pyrochlore iridates Ln2Ir2O7 (Ln = Nd, Sm, and Eu). J. Phys. Soc. Jpn 76, 043706 (2007).

    Article  ADS  Google Scholar 

  12. Matsuhira, K., Wakeshima, M., Hinatsu, Y. & Takagi, S. Metal–insulator transitions in pyrochlore oxides Ln2Ir2O7 . J. Phys. Soc. Jpn 80, 094701 (2011).

    Article  ADS  Google Scholar 

  13. Ishikawa, J. J., O’Farrell, E. C. T. & Nakatsuji, S. Continuous transition between antiferromagnetic insulator and paramagnetic metal in the pyrochlore iridate Eu2Ir2O7 . Phys. Rev. B 85, 245109 (2012).

    Article  ADS  Google Scholar 

  14. Tafti, F. F., Ishikawa, J. J., McCollam, A., Nakatsuji, S. & Julian, S. R. Pressure-tuned insulator to metal transition in Eu2Ir2O7 . Phys. Rev. B 85, 205104 (2012).

    Article  ADS  Google Scholar 

  15. Sagayama, H. et al. Determination of long-range all-in-all-out ordering of Ir4+ moments in a pyrochlore iridate Eu2Ir2O7 by resonant X-ray diffraction. Phys. Rev. B 87, 100403 (2013).

    Article  ADS  Google Scholar 

  16. Machida, Y., Nakatsuji, S., Onoda, S., Tayama, T. & Sakakibara, T. Time-reversal symmetry breaking and spontaneous Hall effect without magnetic dipole order. Nature 463, 210–213 (2010).

    Article  ADS  Google Scholar 

  17. Zhao, S. et al. Magnetic transition, long-range order, and moment fluctuations in the pyrochlore iridate Eu2Ir2O7 . Phys. Rev. B 83, 180402 (2011).

    Article  ADS  Google Scholar 

  18. Yamaura, J. et al. Tetrahedral magnetic order and the metal–insulator transition in the pyrochlore lattice of Cd2Os2O7 . Phys. Rev. Lett. 108, 247205 (2012).

    Article  ADS  Google Scholar 

  19. Tomiyasu, K. et al. Emergence of magnetic long-range order in frustrated pyrochlore Nd2Ir2O7 with metal–insulator transition. J. Phys. Soc. Jpn 81, 034709 (2012).

    Article  ADS  Google Scholar 

  20. Ueda, K. et al. Variation of charge dynamics in the course of metal–insulator transition for pyrochlore-type Nd2Ir2O7 . Phys. Rev. Lett. 109, 136402 (2012).

    Article  ADS  Google Scholar 

  21. Ueda, K. et al. Anomalous domain-wall conductance in pyrochlore-type Nd2Ir2O7 on the verge of the metal–insulator transition. Phys. Rev. B 89, 075127 (2014).

    Article  ADS  Google Scholar 

  22. Ma, E. Y. et al. Mobile metallic domain walls in an all-in-all-out magnetic insulator. Science 350, 538–541 (2015).

    Article  ADS  Google Scholar 

  23. Glazkov, V. N. et al. Single-ion anisotropy in the gadolinium pyrochlores studied by electron paramagnetic resonance. Phys. Rev. B 72, 020409 (2005).

    Article  ADS  Google Scholar 

  24. Glazkov, V. N., Marin, C. & Sanchez, J.-P. Observation of a transverse magnetization in the ordered phases of the pyrochlore magnet Gd2Ti2O7 . J. Phys. Condens. Matter 18, L429–L434 (2006).

    Article  ADS  Google Scholar 

  25. Narumi, Y. et al. High field magnetization of the pyrochlore compound Gd2Ti2O7 . AIP Conf. Proc. 850, 1113–1114 (2006).

    Article  ADS  Google Scholar 

  26. Disseler, S. M. et al. Magnetic order in the pyrochlore iridates A2Ir2O7(A = Y, Yb). Phys. Rev. B 86, 014428 (2012).

    Article  ADS  Google Scholar 

  27. Shapiro, M. C. et al. Structure and magnetic properties of the pyrochlore iridate Y2Ir2O7 . Phys. Rev. B 85, 214434 (2012).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

T.L. acknowledges a scholarship from Japan Student Services Organization. N.P.O. acknowledges the support of the US National Science Foundation (Grant DMR 1420541) and the Gordon and Betty Moore Foundations EPiQS Initiative through Grant GBMF4539. L.F. and T.H.H. were supported by DOE Office of Basic Energy Sciences, DE-SC0010526. T.H.H. thanks the KITP Graduate Fellowship Program. The research at University of Tokyo is supported by grants-in-aid (no. 16H02209) and the Program for Advancing Strategic International Networks to Accelerate the Circulation of Talented Researchers (no. R2604) from JSPS, by CREST of JST, and grant-in-aid for scientific research on Innovative Areas (Grants Nos 15H05882 and 15H05883) from MEXT.

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Author notes

  1. Tian Liang & Timothy H. Hsieh

    Present address: Present addresses: Department of Applied Physics, Stanford University, Stanford, California 94305, USA (T.L.); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106, USA (T.H.H.).,

  2. Tian Liang and Timothy H. Hsieh: These authors contributed equally to this work.

Authors and Affiliations

  1. Department of Physics, Princeton University, Princeton, New Jersey 08544, USA

    Tian Liang & N. P. Ong

  2. Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

    Timothy H. Hsieh & Liang Fu

  3. Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan

    Jun J. Ishikawa & Satoru Nakatsuji

  4. CREST, Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan

    Satoru Nakatsuji

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Contributions

T.L., T.H.H., L.F. and N.P.O. conceived the idea behind the experiment. T.L. designed the experiment and carried out all the measurements. T.L. and N.P.O. analysed the results with important insights from T.H.H. and L.F. The manuscript was written by T.L. and N.P.O. with numerous inputs from T.H.H. and L.F. The high-quality crystal was grown by J.J.I. and S.N. The basic characterization of crystals was made by J.J.I. and S.N. All authors discussed the results and commented on the manuscript.

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Correspondence to Tian Liang or N. P. Ong.

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The authors declare no competing financial interests.

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Liang, T., Hsieh, T., Ishikawa, J. et al. Orthogonal magnetization and symmetry breaking in pyrochlore iridate Eu2Ir2O7. Nature Phys 13, 599–603 (2017). https://doi.org/10.1038/nphys4051

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