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Photonic Weyl points due to broken time-reversal symmetry in magnetized semiconductor

Abstract

Weyl points are discrete locations in the three-dimensional momentum space where two bands cross linearly with each other. They serve as the monopoles of Berry curvature in the momentum space, and their existence requires breaking of either time-reversal or inversion symmetry1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16. Although various non-centrosymmetric Weyl systems have been reported15, demonstration of Weyl degeneracies due to breaking of the time-reversal symmetry remains scarce and is limited to electronic systems17,18. Here, we report the experimental observation of photonic Weyl degeneracies in a magnetized semiconductor—InSb, which behaves as a magnetized plasma19 for electromagnetic waves at the terahertz band. By varying the magnetic field strength, Weyl points and the corresponding photonic Fermi arcs have been demonstrated. Our observation establishes magnetized semiconductors as a reconfigurable20 terahertz Weyl system, which may prompt research on novel magnetic topological phenomena such as chiral Majorana-type edge states and zero modes in classic systems21,22.

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Fig. 1: Bulk states of lossless magnetized InSb.
Fig. 2: Observation of a terahertz Weyl point in a magnetized semiconductor system.
Fig. 3: Surface states under tilted-incidence excitation.
Fig. 4: Photonic Weyl points and Fermi arcs in the synthetic space.

Data availability

The data that support the findings of this study are available from the corresponding authors upon reasonable request.

References

  1. 1.

    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).

    ADS  Google Scholar 

  2. 2.

    Burkov, A. A. & Balents, L. Weyl semimetal in a topological insulator multilayer. Phys. Rev. Lett. 107, 127205 (2011).

    ADS  Google Scholar 

  3. 3.

    Xu, G., Weng, H., Wang, Z., Dai, X. & Fang, Z. Chern semimetal and the quantized anomalous Hall effect in HgCr2Se4. Phys. Rev. Lett. 107, 186806 (2011).

    ADS  Google Scholar 

  4. 4.

    Lu, L., Fu, L., Joannopoulos, J. D. & Soljačić, M. Weyl points and line nodes in gyroid photonic crystals. Nat. Photon. 7, 294–299 (2013).

    ADS  Google Scholar 

  5. 5.

    Xu, S.-Y. et al. Discovery of a Weyl fermion semimetal and topological Fermi arcs. Science 349, 613–617 (2015).

    ADS  Google Scholar 

  6. 6.

    Weng, H., Fang, C., Fang, Z., Bernevig, B. A. & Dai, X. Weyl semimetal phase in noncentrosymmetric transition-metal monophosphides. Phys. Rev. X 5, 011029 (2015).

    Google Scholar 

  7. 7.

    Lu, L. et al. Experimental observation of Weyl points. Science 349, 622–624 (2015).

    ADS  MathSciNet  MATH  Google Scholar 

  8. 8.

    Soluyanov, A. A. et al. Type-II Weyl semimetals. Nature 527, 495–498 (2015).

    ADS  Google Scholar 

  9. 9.

    Huang, L. et al. Spectroscopic evidence for a type II Weyl semimetallic state in MoTe2. Nat. Mater. 15, 1155–1160 (2016).

    ADS  Google Scholar 

  10. 10.

    Lin, Q., Xiao, M., Yuan, L. & Fan, S. Photonic Weyl point in a two-dimensional resonator lattice with a synthetic frequency dimension. Nat. Commun. 7, 13731 (2016).

    ADS  Google Scholar 

  11. 11.

    Chang, G. et al. Room-temperature magnetic topological Weyl fermion and nodal line semimetal states in half-metallic Heusler Co2TiX (X = Si, Ge, or Sn). Sci. Rep. 6, 38839 (2016).

    ADS  Google Scholar 

  12. 12.

    Wang, Z. et al. Time-reversal-breaking Weyl fermions in magnetic Heusler alloys. Phys. Rev. Lett. 117, 236401 (2016).

    ADS  Google Scholar 

  13. 13.

    Kübler, J. & Felser, C. Weyl points in the ferromagnetic Heusler compound Co2MnAl. Europhys. Lett. 114, 47005 (2016).

    ADS  Google Scholar 

  14. 14.

    Wang, Q., Xiao, M., Liu, H., Zhu, S. & Chan, C. T. Optical interface states protected by synthetic Weyl points. Phys. Rev. X 7, 031032 (2017).

    Google Scholar 

  15. 15.

    Armitage, N. P. & Ashvin Vishwanath, E. J. M. Weyl and Dirac semimetals in three-dimensional solids. Rev. Mod. Phys. 90, 015001 (2018).

    ADS  MathSciNet  Google Scholar 

  16. 16.

    Ozawa, T. et al. Topological photonics. Rev. Mod. Phys. 91, 015006 (2019).

    ADS  MathSciNet  Google Scholar 

  17. 17.

    Borisenko, S. et al. Time-reversal symmetry breaking type-II Weyl state in YbMnBi2. Preprint at https://arxiv.org/abs/1507.04847 (2015).

  18. 18.

    Liu, E. et al. Giant anomalous Hall effect in a ferromagnetic kagome-lattice semimetal. Nat. Phys. 14, 1125–1131 (2018).

    Google Scholar 

  19. 19.

    Gao, W. et al. Photonic Weyl degeneracies in magnetized plasma. Nat. Commun. 7, 12435 (2016).

    ADS  Google Scholar 

  20. 20.

    Cheng, X. et al. Robust reconfigurable electromagnetic pathways within a photonic topological insulator. Nat. Mater. 15, 542–548 (2016).

    ADS  Google Scholar 

  21. 21.

    Tan, W., Chen, L., Ji, X. & Lin, H.-Q. Photonic simulation of topological superconductor edge state and zero-energy mode at a vortex. Sci. Rep. 4, 7381 (2014).

    ADS  Google Scholar 

  22. 22.

    Jin, D. et al. Topological magnetoplasmon. Nat. Commun. 7, 13486 (2016).

    ADS  Google Scholar 

  23. 23.

    Goi, E., Yue, Z., Cumming, B. P. & Gu, M. Observation of type I photonic Weyl points in optical frequencies. Laser Photon. Rev. 12, 1700271 (2018).

    ADS  Google Scholar 

  24. 24.

    Chen, W.-J., Xiao, M. & Chan, C. T. Photonic crystals possessing multiple Weyl points and the experimental observation of robust surface states. Nat. Commun. 7, 13038 (2016).

    ADS  Google Scholar 

  25. 25.

    Yang, B. et al. Direct observation of topological surface-state arcs in photonic metamaterials. Nat. Commun. 8, 97 (2017).

    ADS  Google Scholar 

  26. 26.

    Yang, B. et al. Ideal Weyl points and helicoid surface states in artificial photonic crystal structures. Science 359, 1013–1016 (2018).

    ADS  MathSciNet  MATH  Google Scholar 

  27. 27.

    Noh, J. et al. Experimental observation of optical Weyl points and Fermi arc-like surface states. Nat. Phys. 13, 611–617 (2017).

    Google Scholar 

  28. 28.

    O’Brien, T. E., Diez, M. & Beenakker, C. W. J. Magnetic breakdown and Klein tunneling in a type-II Weyl semimetal. Phys. Rev. Lett. 116, 236401 (2016).

    ADS  Google Scholar 

  29. 29.

    Liu, C.-X., Ye, P. & Qi, X.-L. Chiral gauge field and axial anomaly in a Weyl semimetal. Phys. Rev. B 87, 235306 (2013).

    ADS  Google Scholar 

  30. 30.

    Kharzeev, D. E., Kikuchi, Y., Meyer, R. & Tanizaki, Y. Giant photocurrent in asymmetric Weyl semimetals from the helical magnetic effect. Phys. Rev. B 98, 014305 (2018).

    ADS  Google Scholar 

  31. 31.

    Yang, Z. et al. Weyl points in a magnetic tetrahedral photonic crystal. Opt. Express 25, 15772–15777 (2017).

    ADS  Google Scholar 

  32. 32.

    Wang, Z., Chong, Y., Joannopoulos, J. D. & Soljačić, M. Observation of unidirectional backscattering-immune topological electromagnetic states. Nature 461, 772–775 (2009).

    ADS  Google Scholar 

  33. 33.

    Poo, Y., Wu, R.-x, Lin, Z., Yang, Y. & Chan, C. T. Experimental realization of self-guiding unidirectional electromagnetic edge states. Phys. Rev. Lett. 106, 093903 (2011).

    ADS  Google Scholar 

  34. 34.

    Morozov, A. I Introduction to Plasma Dynamics. (CRC: 2012).

  35. 35.

    Zhang, S., Xiong, Y., Bartal, G., Yin, X. & Zhang, X. Magnetized plasma for reconfigurable subdiffraction imaging. Phys. Rev. Lett. 106, 243901 (2011).

    ADS  Google Scholar 

  36. 36.

    Yang, B., Lawrence, M., Gao, W., Guo, Q. & Zhang, S. One-way helical electromagnetic wave propagation supported by magnetized plasma. Sci. Rep. 6, 21461 (2016).

    ADS  Google Scholar 

  37. 37.

    Gangaraj, S. A. H. & Monticone, F. Topological waveguiding near an exceptional point: defect-immune, slow-light, and loss-immune propagation. Phys. Rev. Lett. 121, 093901 (2018).

    ADS  Google Scholar 

  38. 38.

    Hassani Gangaraj, S. A. et al. Unidirectional and diffractionless surface plasmon polaritons on three-dimensional nonreciprocal plasmonic platforms. Phys. Rev. B 99, 245414 (2019).

    ADS  Google Scholar 

  39. 39.

    Howells, S. C. & Schlie, L. A. Transient terahertz reflection spectroscopy of undoped InSb from 0.1 to 1.1 THz. Appl. Phys. Lett. 69, 550–552 (1996).

    ADS  Google Scholar 

  40. 40.

    Wang, X., Belyanin, A. A., Crooker, S. A., Mittleman, D. M. & Kono, J. Interference-induced terahertz transparency in a semiconductor magneto-plasma. Nat. Phys. 6, 126–130 (2009).

    Google Scholar 

  41. 41.

    Zhang, Q. et al. Superradiant decay of cyclotron resonance of two-dimensional electron gases. Phys. Rev. Lett. 113, 047601 (2014).

    ADS  Google Scholar 

  42. 42.

    Buddhiraju, S. et al. Absence of unidirectionally propagating surface plasmon-polaritons in nonreciprocal plasmonics. Preprint at https://arxiv.org/abs/1809.05100 (2018).

  43. 43.

    Hassani Gangaraj, S. A. & Monticone, F. Do truly unidirectional surface plasmon-polaritons exist?. Preprint at https://arxiv.org/abs/1904.08392 (2019).

  44. 44.

    Jia, H. et al. Observation of chiral zero mode in inhomogeneous three-dimensional Weyl metamaterials. Science 363, 148–151 (2019).

    ADS  MathSciNet  Google Scholar 

  45. 45.

    Gooth, J. et al. Experimental signatures of the mixed axial–gravitational anomaly in the Weyl semimetal NbP. Nature 547, 324–327 (2017).

    ADS  Google Scholar 

Download references

Acknowledgements

We thank Z. Zhang and C. Zhang at Capital Normal University for experimental instrument support. This work is supported by the European Research Council Consolidator Grant (TOPOLOGICAL), Horizon 2020 Action Project grant 734578 (D-SPA) and 777714 (NOCTORNO), EPSRC grant no. EP/J018473/1 and the National Science Foundation of China (grant nos. 61875150 and 61420106006). S.Z. acknowledges support from the Royal Society and the Wolfson Foundation. M.N.-C. acknowledges support from the University of Birmingham (Birmingham Fellowship), the EPSRC (grant no. EP/S018395/1) and the Royal Society (grant no. IES/R3/183131).

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Contributions

D.W., B.Y. and S.Z. initiated the project and designed the experiment. D.W., Q.Y., X.C., M.W. and J.H. fabricated samples. D.W. and J.H. carried out the measurements. D.W., B.Y., J.H., W.Z. and S.Z. analysed data. D.W., B.Y., W.G., H.J., M.N.-C. and C.L. performed simulations. D.W., B.Y., W.G., M.N.-C., J.H., W.Z. and S.Z. provided the theoretical explanations. J.H., W.Z. and S.Z. supervised the project. All authors discussed the results and contributed to the final manuscript.

Corresponding authors

Correspondence to Jiaguang Han or Weili Zhang or Shuang Zhang.

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Peer review information: Nature Physics thanks Francesco Monticone, Giacomo Scalari and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Wang, D., Yang, B., Gao, W. et al. Photonic Weyl points due to broken time-reversal symmetry in magnetized semiconductor. Nat. Phys. 15, 1150–1155 (2019). https://doi.org/10.1038/s41567-019-0612-7

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