Parametrically amplified phase-incoherent superconductivity in YBa$_2$Cu$_3$O$_{6+x}$
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arXiv
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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
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2019
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| _version_ | 1866911951313960960 |
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| author | von Hoegen, A. Fechner, M. Först, M. Taherian, N. Rowe, E. Ribak, A. Porras, J. Keimer, B. Michael, M. Demler, E. Cavalleri, A. |
| author_facet | von Hoegen, A. Fechner, M. Först, M. Taherian, N. Rowe, E. Ribak, A. Porras, J. Keimer, B. Michael, M. Demler, E. Cavalleri, A. |
| contents | The possibility of enhancing desirable functional properties of complex materials by optical driving is motivating a series of studies of their nonlinear terahertz response. In high-Tc cuprates, large amplitude excitation of certain infrared-active lattice vibrations has been shown to induce transient features in the reflectivity suggestive of non-equilibrium superconductivity. Yet, a microscopic mechanism for these observations is still lacking. Here, we report measurements of time- and scattering-angle-dependent second-harmonic generation in YBa$_2$Cu$_3$O$_{6+x}$, taken under the same excitation conditions that result in superconductor-like terahertz reflectivity. We discover a three-order-of-magnitude amplification of a 2.5-terahertz electronic mode, which is unique because of its symmetry, momentum, and temperature dependence. A theory for parametric three-wave amplification of Josephson plasmons, which are assumed to be well-formed below T$_c$ but overdamped throughout the pseudogap phase, explains all these observations and provides a mechanism for non-equilibrium superconductivity. More broadly, our work underscores the role of parametric mode mixing to stabilize fluctuating orders in quantum materials. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_1911_08284 |
| institution | arXiv |
| publishDate | 2019 |
| record_format | arxiv |
| spellingShingle | Parametrically amplified phase-incoherent superconductivity in YBa$_2$Cu$_3$O$_{6+x}$ von Hoegen, A. Fechner, M. Först, M. Taherian, N. Rowe, E. Ribak, A. Porras, J. Keimer, B. Michael, M. Demler, E. Cavalleri, A. Superconductivity Strongly Correlated Electrons The possibility of enhancing desirable functional properties of complex materials by optical driving is motivating a series of studies of their nonlinear terahertz response. In high-Tc cuprates, large amplitude excitation of certain infrared-active lattice vibrations has been shown to induce transient features in the reflectivity suggestive of non-equilibrium superconductivity. Yet, a microscopic mechanism for these observations is still lacking. Here, we report measurements of time- and scattering-angle-dependent second-harmonic generation in YBa$_2$Cu$_3$O$_{6+x}$, taken under the same excitation conditions that result in superconductor-like terahertz reflectivity. We discover a three-order-of-magnitude amplification of a 2.5-terahertz electronic mode, which is unique because of its symmetry, momentum, and temperature dependence. A theory for parametric three-wave amplification of Josephson plasmons, which are assumed to be well-formed below T$_c$ but overdamped throughout the pseudogap phase, explains all these observations and provides a mechanism for non-equilibrium superconductivity. More broadly, our work underscores the role of parametric mode mixing to stabilize fluctuating orders in quantum materials. |
| title | Parametrically amplified phase-incoherent superconductivity in YBa$_2$Cu$_3$O$_{6+x}$ |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/1911.08284 |