Evidence of a photoinduced non-thermal superconducting-to-normal-state phase transition in overdoped Bi$_{2}$Sr$_{2}$Ca$_{0.92}$Y$_{0.08}$Cu$_{2}$O$_{8+\delta}$

TL;DR

This study uses ultrafast reflectivity to show that photoinduced transition from superconducting to normal state in overdoped Bi-based cuprates is non-thermal, differing from thermal and other photoinduced phase transitions, and raises questions about its nature.

Contribution

It provides evidence of a non-thermal superconducting-to-normal phase transition induced by light, analyzed with a new time-dependent Rothwarf-Taylor model, advancing understanding of non-equilibrium states.

Findings

No quasiparticle decay time divergence at transition fluence

Transition is non-thermal in nature

Data analyzed with a novel time-dependent model

Abstract

Here we report extensive ultrafast time-resolved reflectivity experiments on overdoped Bi$_{2}$Sr$_{2}$Ca$_{1-x}$Y$_x$Cu$_{2}$O$_{8+\delta}$ single crystals (T$_C$=78 K) aimed to clarify the nature of the superconducting-to-normal-state photoinduced phase transition. The experimental data show the lack of the quasiparticles decay time divergence at the fluence required to induce this phase transition, in contrast to the thermally-driven phase transition observed at T$_C$ and at variance with recently reported photoinduced charge-density-wave and spin-density-wave to metal phase transitions. Our data demonstrate the non-thermal character of the superconducting-to-normal-state photoinduced phase transition. The data have been analyzed using an ad-hoc developed time-dependent Rothwarf-Taylor model, opening the question on the order of this non-equilibrium phase transition.