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Exciton Hall effect in monolayer MoS2

Abstract

The spontaneous Hall effect driven by the quantum Berry phase (which serves as an internal magnetic flux in momentum space) manifests the topological nature of quasiparticles and can be used to control the information flow, such as spin and valley1,2. We report a Hall effect of excitons (fundamental composite particles of electrons and holes that dominate optical responses in semiconductors3). By polarization-resolved photoluminescence mapping, we directly observed the Hall effect of excitons in monolayer MoS2 and valley-selective spatial transport of excitons on a micrometre scale. The Hall angle of excitons is found to be much larger than that of single electrons in monolayer MoS2 (ref. 4), implying that the quantum transport of the composite particles is significantly affected by their internal structures. The present result not only poses a fundamental problem of the Hall effect in composite particles, but also offers a route to explore exciton-based valleytronics in two-dimensional materials.

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Figure 1: Experimental concept of the exciton Hall effect in monolayer MoS2.
Figure 2: Diffusion of excitons in monolayer MoS2.
Figure 3: The exciton Hall effect.
Figure 4: Selective spatial transport of valley-polarized excitons.

References

  1. 1

    Xiao, D., Chang, M.-C. & Niu, Q. Berry phase effects on electronic properties. Rev. Mod. Phys. 82, 1959–2007 (2010).

    CAS  Article  Google Scholar 

  2. 2

    Sinova, J., Valenzuela, S. O., Wunderlich, J., Back, C. H. & Jungwirth, T. Spin Hall effects. Rev. Mod. Phys. 87, 1213–1259 (2015).

    Article  Google Scholar 

  3. 3

    Elliott, R. J. Intensity of optical absorption by excitons. Phys. Rev. 108, 1384–1389 (1957).

    CAS  Article  Google Scholar 

  4. 4

    Mak, K. F., McGill, K. L., Park, J. & McEuen, P. L. The valley Hall effect in MoS2 transistors. Science 344, 1489–1492 (2014).

    CAS  Article  Google Scholar 

  5. 5

    Hall, E. H. On a new action of the magnet on electric currents. Am. J. Math. 2, 287–292 (1879).

    Article  Google Scholar 

  6. 6

    Xiao, D., Liu, G. B., Feng, W., Xu, X. & Yao, W. Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides. Phys. Rev. Lett. 108, 196802 (2012).

    Article  Google Scholar 

  7. 7

    Strohm, C., Rikken, G. L. J. A. & Wyder, P. Phenomenological evidence for the phonon Hall effect. Phys. Rev. Lett. 95, 155901 (2005).

    CAS  Article  Google Scholar 

  8. 8

    Onose, Y. et al. Observation of the Magnon Hall effect. Science 329, 297–299 (2010).

    CAS  Article  Google Scholar 

  9. 9

    Yao, W. & Niu, Q. Berry phase effect on the exciton transport and on the exciton Bose–Einstein condensate. Phys. Rev. Lett. 101, 106401 (2008).

    Article  Google Scholar 

  10. 10

    Kuga, S., Murakami, S. & Nagaosa, N. Spin Hall effect of excitons. Phys. Rev. B 78, 205201 (2008).

    Article  Google Scholar 

  11. 11

    Yu, H., Liu, G.-B., Gong, P., Xu, X. & Yao, W. Dirac cones and Dirac saddle points of bright excitons in monolayer transition metal dichalcogenides. Nat. Commun. 5, 3876 (2014).

    CAS  Article  Google Scholar 

  12. 12

    Li, Y.-M. et al. Light-induced exciton spin Hall effect in van der Waals heterostructures. Phys. Rev. Lett. 115, 166804 (2015).

    Article  Google Scholar 

  13. 13

    Yu, T. & Wu, M. W. Valley depolarization dynamics and valley Hall effect of excitons in monolayer and bilayer MoS2 . Phys. Rev. B 93, 045414 (2016).

    Article  Google Scholar 

  14. 14

    Mak, K. F., Lee, C., Hone, J., Shan, J. & Heinz, T. F. Atomically thin MoS2: a new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010).

    Article  Google Scholar 

  15. 15

    Splendiani, A. et al. Emerging photoluminescence in monolayer MoS2 . Nano Lett. 10, 1271–1275 (2010).

    CAS  Article  Google Scholar 

  16. 16

    Zhang, C., Johnson, A., Hsu, C., Li, L. & Shih, C. Direct imaging of band profile in single layer MoS2 on graphite: quasiparticle energy gap, metallic edge states, and edge band bending. Nano Lett. 14, 2443–2447 (2014).

    CAS  Article  Google Scholar 

  17. 17

    Mak, K. F., He, K., Shan, J. & Heinz, T. F. Control of valley polarization in monolayer MoS2 by optical helicity. Nat. Nanotech. 7, 494–498 (2012).

    CAS  Article  Google Scholar 

  18. 18

    Zeng, H., Dai, J., Yao, W., Xiao, D. & Cui, X. Valley polarization in MoS2 monolayers by optical pumping. Nat. Nanotech. 7, 490–493 (2012).

    CAS  Article  Google Scholar 

  19. 19

    Jones, A. M. et al. Optical generation of excitonic valley coherence in monolayer WSe2 . Nat. Nanotech. 8, 634–638 (2013).

    CAS  Article  Google Scholar 

  20. 20

    Srivastava, A. et al. Valley Zeeman effect in elementary optical excitations of a monolayer WSe2 . Nat. Phys. 11, 141–147 (2015).

    CAS  Article  Google Scholar 

  21. 21

    Aivazian, G. et al. Magnetic control of valley pseudospin in monolayer WSe2 . Nat. Phys. 11, 148–152 (2015).

    CAS  Article  Google Scholar 

  22. 22

    Korn, T., Heydrich, S., Hirmer, M., Schmutzler, J. & Schller, C. Low-temperature photocarrier dynamics in monolayer MoS2 . Appl. Phys. Lett. 99, 2014–2017 (2011).

    Article  Google Scholar 

  23. 23

    Mouri, S. et al. Nonlinear photoluminescence in atomically thin layered WSe2 arising from diffusion-assisted exciton–exciton annihilation. Phys. Rev. B 90, 155449 (2014).

    Article  Google Scholar 

  24. 24

    Cui, Q., Ceballos, F., Kumar, N. & Zhao, H. Transient absorption microscopy of monolayer and bulk WSe2 . ACS Nano 8, 2970–2976 (2014).

    CAS  Article  Google Scholar 

  25. 25

    Rivera, P. et al. Valley-polarized exciton dynamics in a 2D semicondcutor heterostructure. Science 351, 688–691 (2016).

    CAS  Article  Google Scholar 

  26. 26

    Kato, Y. K., Myers, R. C., Gossard, A. C. & Awschalom, D. D. Observation of the spin Hall effect in semiconductors. Science 306, 1910–1913 (2004).

    CAS  Article  Google Scholar 

  27. 27

    Lee, J., Mak, K. F. & Shan, J. Electrical control of the valley Hall effect in bilayer MoS2 transistors. Nat. Nanotech. 11, 421–425 (2015).

    Article  Google Scholar 

  28. 28

    Leyder, C. et al. Observation of the optical spin Hall effect. Nat. Phys. 3, 628–631 (2007).

    CAS  Article  Google Scholar 

  29. 29

    Mak, K. F. et al. Tightly bound trions in monolayer MoS2 . Nat. Mater. 12, 207–211 (2013).

    CAS  Article  Google Scholar 

  30. 30

    Xie, L. & Cui, X. Manipulating spin-polarized photocurrents in 2D transition metal dichalcogenides. Proc. Natl Acad. Sci. USA 113, 3746–3750 (2016).

    CAS  Article  Google Scholar 

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Acknowledgements

We thank N. Nagaosa, A. Fujimori, M. Yoshida and F. Qin for helpful discussions. M.O. is supported by Advanced Leading Graduate Course for Photon Science (ALPS). M.O. and Y.Z. were supported by Japan Society for the Promotion of Science (JSPS) through the Research Fellowship for Young Scientists. T.I. was supported by Grant-in-Aid for Research Activity Start-up (No. JP15H06133) and Challenging Research (Exploratory) (No. JP17K18748) from JSPS. This research was supported by Grant-in-Aid for specially promoted research (No. 25000003) from JSPS.

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All authors conceived and designed the research. M.O. and Y.Z. built the measurement system. M.O. performed the measurements and analysed the data. All authors discussed the results and wrote the manuscript.

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Correspondence to Yoshihiro Iwasa.

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The authors declare no competing financial interests.

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Onga, M., Zhang, Y., Ideue, T. et al. Exciton Hall effect in monolayer MoS2. Nature Mater 16, 1193–1197 (2017). https://doi.org/10.1038/nmat4996

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