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Lightwave-driven gapless superconductivity and forbidden quantum beats by terahertz symmetry breaking

Nature Photonics volume 13, pages 707–713 (2019)Cite this article

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An Author Correction to this article was published on 12 July 2019

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Abstract

Light-induced supercurrents chart a path forward for the electromagnetic design of emergent materials phases and collective modes for quantum engineering applications. However, controlled spatial–temporal modulation of the complex order parameter characterizing such non-equilibrium macroscopic quantum states remains elusive. Such ultrafast phase-amplitude modulation can manifest via high harmonic modes beyond those allowed by equilibrium symmetries. Here, we drive moving condensate states via subcycle dynamical symmetry breaking achieved with nonlinear oscillating terahertz photocurrents. These non-equilibrium macroscopic quantum states with broken inversion symmetry are controlled via Cooper pair acceleration by asymmetric and multi-cycle terahertz photoexcitations. The observed supercurrent-carrying states evolve during a lightwave cycle and exhibit three distinguishing features: Anderson pseudo-spin precessions forbidden by equilibrium symmetry, strong high harmonic coherent oscillations assisted by pairing and long-lived gapless superfluidity with minimal condensate quench. Lightwave tuning of persistent photocurrents can be extended for quantum control of unconventional superconductors and topological matter, with implications on quantum gate and sensing functionalities.

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Fig. 1: Pseudo-spin coherent oscillations forbidden by equilibrium symmetry and strong HH generation nonlinearities.
Fig. 2: Lightwave-driven collective modes with different THz nonlinear and asymmetric driving.
Fig. 3: Light-driven gapless superconductivity by non-thermal control of the supercurrent-carrying quantum states.
Fig. 4: Gauge-invariant quantum kinetic calculation of the density matrix for the periodically driven, supercurrent-carrying macroscopic state.

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The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

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  • 12 July 2019

    An amendment to this paper has been published and can be accessed via a link at the top of the paper.

References

  1. Aoki, H. et al. Nonequilibrium dynamical mean-field theory and its applications. Rev. Mod. Phys. 86, 779–837 (2014).

    Article  ADS  Google Scholar 

  2. Cea, T., Barone, P., Castellani, C. & Benfatto, L. Polarization dependence of the third-harmonic generation in multiband superconductors. Phys. Rev. B 97, 094516 (2018).

    Article  ADS  Google Scholar 

  3. Matsunaga, R. et al. Higgs amplitude mode in the BCS superconductors Nb1 − xTixN induced by terahertz pulse excitation. Phys. Rev. Lett. 111, 057002 (2013).

    Article  ADS  Google Scholar 

  4. Matsunaga, R. et al. Light-induced collective pseudospin precession resonating with Higgs mode in a superconductor. Science 345, 1145–1149 (2014).

    Article  ADS  MathSciNet  Google Scholar 

  5. Papenkort, T., Axt, V. M. & Kuhn, T. Coherent dynamics and pump–probe spectra of BCS superconductors. Phys. Rev. B 76, 224522 (2007).

    Article  ADS  Google Scholar 

  6. Rajasekaran, S. et al. Probing optically silent superfluid stripes in cuprates. Science 359, 575–579 (2018).

    Article  ADS  MathSciNet  Google Scholar 

  7. Yang, X. et al. Terahertz-light quantum tuning of a metastable emergent phase hidden by superconductivity. Nat. Mater. 17, 586–591 (2018).

    Article  ADS  Google Scholar 

  8. Nakamura, S. et al. Infrared activation of Higgs mode by supercurrent injection in a superconductor NbN. Preprint at http://arxiv.org/abs/1809.10335 (2018).

  9. Luo, L. et al. Ultrafast terahertz conductivity probes of topologically enhanced surface transport driven by mid-infrared laser pulse in Bi2Se3. Nat. Commun. 10, 607 (2019).

    Article  ADS  Google Scholar 

  10. Reimann, J. et al. Subcycle observation of lightwave-driven Dirac currents in a topological surface band. Nature 562, 396–400 (2018).

    Article  ADS  Google Scholar 

  11. Fausti, D. et al. Light-induced superconductivity in a stripe-ordered cuprate. Science 331, 189–191 (2011).

    Article  ADS  Google Scholar 

  12. Beck, M. et al. Transient increase of the energy gap of superconducting NbN thin films excited by resonant narrow-band terahertz pulses. Phys. Rev. Lett. 110, 267003 (2013).

    Article  ADS  Google Scholar 

  13. Giorgianni, F. et al. Leggett mode controlled by light pulses. Nat. Phys. 15, 341–346 (2019).

    Article  Google Scholar 

  14. Mansarta, B. et al. Coupling of a high-energy excitation to superconducting quasiparticles in a cuprate from coherent charge fluctuation spectroscopy. Proc. Natl Acad. Sci. USA 110, 4539–4544 (2013).

    Article  ADS  Google Scholar 

  15. Pekker, D. & Varma, C. M. Amplitude/Higgs modes in condensed matter physics. Annu. Rev. Condens. Matter Phys. 6, 269–297 (2015).

    Article  ADS  Google Scholar 

  16. Matsunaga, R. et al. Polarization-resolved terahertz third-harmonic generation in a single-crystal superconductor NbN: dominance of the Higgs mode beyond the BCS approximation. Phys. Rev. B 96, 020505(R) (2017).

    Article  ADS  Google Scholar 

  17. Kozlov, V. V., Rosanov, N. N., De Angelis, C. & Wabnitz, S. Generation of unipolar pulses from nonunipolar optical pulses in a nonlinear medium. Phys. Rev. A 84, 023818 (2011).

    Article  ADS  Google Scholar 

  18. Anthore, A., Pothier, H. & Esteve, D. Density of states in a superconductor carrying a supercurrent. Phys. Rev. Lett. 90, 127001 (2003).

    Article  ADS  Google Scholar 

  19. Yuzbashyan, E. A. & Dzero, M. Dynamical vanishing of the order parameter in a fermionic condensate. Phys. Rev. Lett. 96, 230404 (2006).

    Article  ADS  Google Scholar 

  20. Luo, L. et al. Broadband terahertz generation from metamaterials. Nat. Commun. 5, 3055 (2014).

    Article  ADS  Google Scholar 

  21. Yang, X. et al. Ultrafast nonthermal terahertz electrodynamics and possible quantum energy transfer in the Nb3Sn superconductor. Phys. Rev. B. 99, 094504 (2019).

    Article  ADS  Google Scholar 

  22. Semenov, A. V., Devyatov, I. A., de Visser, P. J. & Klapwijk, T. M. Coherent excited states in superconductors due to a microwave field. Phys. Rev. Lett. 117, 047002 (2016).

    Article  ADS  Google Scholar 

  23. Moor, A., Volkov, A. F. & Efetov, K. B. Amplitude Higgs mode and admittance in superconductors with a moving condensate. Phys. Rev. Lett. 118, 047001 (2017).

    Article  ADS  Google Scholar 

  24. Hansen, E. B. Infinite conductivity of ordinary and gapless superconductors. Physica 39, 271–292 (1968).

    Article  ADS  Google Scholar 

  25. Dzero, M., Khodas, M. & Levchenko, A. Amplitude modes and dynamic coexistence of competing orders in multicomponent superconductors. Phys. Rev. B 91, 214505 (2015).

    Article  ADS  Google Scholar 

  26. Yang, X. et al. Nonequilibrium pair breaking in Ba(Fe1 − xCox)2As2 superconductors: evidence for formation of photoinduced excitonic state. Phys. Rev. Lett. 121, 267001 (2018).

    Article  ADS  Google Scholar 

  27. Patz, A. et al. Ultrafast observation of critical nematic fluctuations and giant magnetoelastic coupling in iron pnictides. Nat. Commun. 5, 3229 (2014).

    Article  ADS  Google Scholar 

  28. Patz, A. et al. Critical speeding-up of non-equilibrium electronic relaxation near nematic phase transition in unstrained Ba(Fe1 − xCox)2As2. Phys. Rev. B 95, 165122 (2017).

    Article  ADS  Google Scholar 

  29. Langer, F. et al. Lightwave valleytronics in a monolayer of tungsten diselenide. Nature 557, 76–80 (2018).

    Article  ADS  Google Scholar 

  30. Stephen, M. J. Transport equations for superconductors. Phys. Rev. 139, A197 (1965).

    Article  ADS  MathSciNet  Google Scholar 

  31. Yang, F. & Wu, M. W. Gauge-invariant microscopic kinetic theory of superconductivity in response to electromagnetic fields. Phys. Rev. B 98, 094507 (2018).

    Article  ADS  Google Scholar 

  32. Chou, Y. Z., Liao, Y. & Foster, M. S. Twisting Anderson pseudospins with light: quench dynamics in terahertz-pumped BCS superconductors. Phys. Rev. B 95, 104507 (2017).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

Work at Iowa State University was supported by the Army Research Office under award no. W911NF-15-1-0135 (THz quantum spectroscopy). Work at the University of Wisconsin was supported by funding from the Department of Energy Office of Basic Energy Sciences under award no. DE-FG02-06ER46327 (structural and electrical characterizations) and Department of Energy grant no. DE-SC100387-020 (thin-film synthesis). The theory work at the University of Alabama, Birmingham was supported by the US Department of Energy, Office of Science, Basic Energy Sciences under award no. DE-SC0019137. The THz spectroscopy instrument was supported in part by the W.M. Keck Foundation.

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Authors and Affiliations

  1. Department of Physics and Astronomy, Iowa State University and Ames Laboratory – USDOE, Ames, IA, USA

    X. Yang, C. Vaswani, L. Luo & J. Wang

  2. Department of Materials Science and Engineering, University of Wisconsin–Madison, Madison, WI, USA

    C. Sundahl, J. H. Kang & C. B. Eom

  3. Department of Physics, University of Alabama at Birmingham, Birmingham, AL, USA

    M. Mootz & I. E. Perakis

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  1. X. Yang
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  5. L. Luo
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  9. J. Wang
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Contributions

X.Y., C.V. and J.W. performed the experimental measurements, collected the data and analysed the results. C.S., J.H.K. and C.B.E. designed, fabricated and characterized the thin film heterostructures. M.M. and I.E.P. developed the theory and performed the quantum kinetic calculations. J.W. supervised the study, and wrote the paper together with I.E.P. and with help from all authors.

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Correspondence to J. Wang.

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Yang, X., Vaswani, C., Sundahl, C. et al. Lightwave-driven gapless superconductivity and forbidden quantum beats by terahertz symmetry breaking. Nat. Photonics 13, 707–713 (2019). https://doi.org/10.1038/s41566-019-0470-y

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