Non-monotonic superconducting transition in YBCO thin films under laser irradiation

Abstract

Laser-induced nonequilibrium dynamics in high-temperature superconductors offer a nondestructive approach to perturb the electronic, spin, and lattice degrees of freedom and are essential for the development of next-generation high-performance devices. In this work, we fabricated high-quality YBa2Cu3O7−δ (YBCO) thin films via pulsed laser deposition and systematically investigated their photoresponse under visible light irradiation, integrating results from thickness-dependent (15–300 nm), wavelength-dependent (400–900 nm), and magnetic field-modulated experiments. Notably, the superconducting transition temperature (Tc) of the YBCO films exhibits two distinct dome-shaped regions with dual maxima as a function of laser irradiation power. The observed non-monotonic superconducting behavior is attributed to the synergistic effects of oxygen stoichiometry modulation, nonequilibrium carrier dynamics, and lattice dynamics. Our findings reveal rich nonequilibrium superconducting dynamics, manifested as a tunable double-dome Tc evolution with laser power, and provide key insights into the competing interactions governing high-temperature superconductivity in YBCO.