Pseudogap in electron-doped cuprates: thermal precursor to magnetism

TL;DR

This paper investigates the pseudogap phenomenon in electron-doped cuprates, linking it to thermal magnetic fluctuations and analyzing spectral functions, with implications for understanding magnetically-mediated superconductivity.

Contribution

It provides a detailed theoretical analysis of pseudogap behavior related to thermal magnetic fluctuations and compares results with recent ARPES experiments.

Findings

Pseudogap manifests as peaks at finite frequency in EDCs.

MDC peaks disperse within the pseudogap, ending at a gossamer Fermi surface.

Thermal fluctuations nearly cancel in the superconducting gap equation.

Abstract

We study pseudogap behavior in a metal near an antiferromagnetic instability and apply the results to electron-doped cuprates. We associate pseudogap behavior with thermal magnetic fluctuations and compute the fermionic self-energy along the Fermi surface beyond Eliashberg approximation. We analyze the spectral function as a function of frequency (energy distribution curves, EDC) and momentum (momentum distribution curves, MDC). We show that the EDC display pseudogap behavior with peaks at a finite frequency at all momenta. On the other hand, MDC peaks disperse within the pseudogap, ending at a gossamer Fermi surface. We analyze magnetically-mediated superconductivity and show that thermal fluctuations almost cancel out in the gap equation, even when the self-energy is obtained beyond the Eliashberg approximation. We favorably compare our results with recent ARPES study [K-J Xu et al, Nat. Phys. 19, 1834-1840 (2023)].