Melting the Superconducting State in the Electron Doped Cuprate Pr$_{1.85}% $Ce$_{0.15}$CuO$_{4-\delta}$ with Intense near-infrared and Terahertz Pulses

TL;DR

This study investigates how intense near-infrared and terahertz pulses deplete superconductivity in an electron-doped cuprate, revealing different energy thresholds and insights into the pairing mechanism.

Contribution

It demonstrates that terahertz pulses can deplete superconductivity at energies matching the condensation energy, unlike near-infrared pulses, providing new insights into pairing interactions.

Findings

THz pulses deplete superconductivity at the thermodynamic energy

NIR pulses require much higher energy to deplete SC

Only a small subset of bosons contribute to pairing

Abstract

We studied the superconducting (SC) state depletion process in an electron doped cuprate Pr$_{1.85}$Ce$_{0.15}$CuO$_{4-\delta}$ by pumping with near-infrared (NIR) and narrow-band THz pulses. When pumping with THz pulses tuned just above the SC gap, we find the absorbed energy density required to deplete superconductivity, $A_{dep}$, matches the thermodynamic condensation energy. Contrary, by NIR pumping $A_{dep}$ is an order of magnitude higher, despite the fact that the SC gap is much smaller than the energy of relevant bosonic excitations. The result implies that only a small subset of bosons contribute to pairing.