Identifying a forward-scattering superconductor through pump-probe spectroscopy

¹ Department of Physics, North Carolina State University - Raleigh, NC 27695, USA
² Department of Physics and Astronomy, The University of Tennessee - Knoxville, TN 37996, USA

^(a) akumar13@ncsu.edu
^(b) akemper@ncsu.edu

Received: 20 August 2018
Accepted: 10 December 2018

Abstract

Electron-boson scattering that is peaked in the forward direction has been suggested as an essential ingredient for enhanced superconductivity observed in FeSe monolayers. Here, we study the superconducting state of a system dominated by forward scattering in the time domain and contrast its behavior against the standard isotropic BCS case for both s- and d-wave symmetries. An analysis of the electron's dynamics in the pump-driven non-equilibrium state reveals that the superconducting order in the forward-focused case is robust and persistent against the pump-induced perturbations. The superconducting order parameter also exhibits a non-uniform melting in momentum space. We show that this behavior is in sharp contrast to the isotropic interaction case and propose that time-resolved approaches are a potentially powerful tool to differentiate the nature of the dominant coupling in correlated materials.