We successfully fabricated and studied planar superconductor-normal-superconductor (SNS) Josephson junctions made of ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ (YBCO) high- ${\mathrm{T}}_{C}$ superconductor (S) and Au normal metal (N). The crucial step in fabrication was done by using a Pt/Au bilayer encapsulation of the patterned YBCO nanogap. This procedure preserves the YBCO nanogap from the degradation due to the contact with resists, water, and chemicals involved in further processing for hybrid devices. The junctions exhibit Fraunhofer-like modulation patterns and Shapiro steps when they are irradiated by a rf field. Furthermore, we analyzed the ${I}_{C}(T)$ characteristics of our hybrid junctions employing a ${\mathrm{SINI}}^{\ensuremath{'}}\mathrm{S}$ (superconductor--insulator--normal conductor--insulator--superconductor) model.We successfully fabricated and studied planar superconductor-normal-superconductor (SNS) Josephson junctions made of ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ (YBCO) high-${\mathrm{T}}_{C}$ superconductor (S) and Au normal metal (N). The crucial step in fabrication was done by using a Pt/Au bilayer encapsulation of the patterned YBCO nanogap. This procedure preserves the YBCO nanogap from the degradation due to the contact with resists, water, and chemicals involved in further processing for hybrid devices. The junctions exhibit Fraunhofer-like modulation patterns and Shapiro steps when they are irradiated by a rf field. Furthermore, we analyzed the ${I}_{C}(T)$ characteristics of our hybrid junctions employing a ${\mathrm{SINI}}^{\ensuremath{'}}\mathrm{S}$ (superconductor--insulator--normal conductor--insulator--superconductor) model.

Physical review. B./Physical review. BMay 17, 201710 citations

Quantum critical behaviour in a high-Tc superconductor

D. van der Marel, H. J. A. Molegraaf, Jan Zaanen +7 more

arXiv:cond-mat/0309172NatureSep 1, 2003363 citations

Macroscopic Quantum Phenomena in High Critical Temperature Superconducting Josephson Junctions

T. Claeson, Floriana Lombardi, Thilo Bauch +5 more

Journal of Superconductivity and Novel MagnetismDec 20, 20061 citation

High-harmonic spectroscopy of quantum phase transitions in a high-Tc superconductor

Jordi Alcalà, Utso Bhattacharya, Jens Biegert +9 more

We report on the nonlinear optical signatures of quantum phase transitions in the high-temperature superconductor YBCO, observed through high harmonic generation. While the linear optical response of the material is largely unchanged when cooling across the phase transitions, the nonlinear optical response sensitively imprints two critical points, one at the critical temperature of the cuprate with the exponential growth of the surface harmonic yield in the superconducting phase and another critical point, which marks the transition from strange metal to pseudogap phase. To reveal the underlying microscopic quantum dynamics, a strong-field quasi-Hubbard model was developed, which describes the measured optical response dependent on the formation of Cooper pairs. Further, the theory provides insight into the carrier scattering dynamics and allows us to differentiate between the superconducting, pseudogap, and strange metal phases. The direct connection between nonlinear optical response and microscopic dynamics provides a powerful methodology to study quantum phase transitions in correlated materials. Further implications are light wave control over intricate quantum phases, light-matter hybrids, and application for optical quantum computing.We report on the nonlinear optical signatures of quantum phase transitions in the high-temperature superconductor YBCO, observed through high harmonic generation. While the linear optical response of the material is largely unchanged when cooling across the phase transitions, the nonlinear optical response sensitively imprints two critical points, one at the critical temperature of the cuprate with the exponential growth of the surface harmonic yield in the superconducting phase and another critical point, which marks the transition from strange metal to pseudogap phase. To reveal the underlying microscopic quantum dynamics, a strong-field quasi-Hubbard model was developed, which describes the measured optical response dependent on the formation of Cooper pairs. Further, the theory provides insight into the carrier scattering dynamics and allows us to differentiate between the superconducting, pseudogap, and strange metal phases. The direct connection between nonlinear optical response and microscopic dynamics provides a powerful methodology to study quantum phase transitions in correlated materials. Further implications are light wave control over intricate quantum phases, light-matter hybrids, and application for optical quantum computing.

Proceedings of the National Academy of SciencesSep 26, 202262 citations

Theory of macroscopic quantum tunneling in Nb/Au/YBCO Josephson junctions

Shiro Kawabata, Alexander A. Golubov, Ariando Ariando +2 more

Physica C SuperconductivityMay 19, 20071 citation

Quantum monte carlo simulations for high-Tc superconductors

A. Muramatsu, G. Dopf, J. Wagner +2 more

Advances in Solid State PhysicsSep 11, 20071 citation

{\mathrm{T}}_{C}

superconductor (S) and Au normal metal (N). The crucial step in fabrication was done by using a Pt/Au bilayer encapsulation of the patterned YBCO nanogap. This procedure preserves the YBCO nanogap from the degradation due to the contact with resists, water, and chemicals involved in further processing for hybrid devices. The junctions exhibit Fraunhofer-like modulation patterns and Shapiro steps when they are irradiated by a rf field. Furthermore, we analyzed the

{I}_{C}(T)

characteristics of our hybrid junctions employing a ${\mathrm{SINI}}^{\ensuremath{'}}\mathrm{S}$ (superconductor--insulator--normal conductor--insulator--superconductor) model.