Low-energy excitations around (\pi/2, \pi/2) points in the pseudogap phase of Nd_1.85Ce_0.15CuO_4

TL;DR

This study uses polarized Raman scattering to investigate the pseudogap phase in Nd_1.85Ce_0.15CuO_4, revealing anisotropic gap formation and long-lived excitations near specific momentum points below a characteristic temperature.

Contribution

It provides new insights into the momentum-dependent pseudogap and excitations in electron-doped cuprates using Raman spectroscopy.

Findings

Pseudogap forms below T* ~ 220 K with energy E*_g = 850 cm-1.

Suppression of spectral weight occurs in the nodal directions below T*.

Long-lived excitations emerge near (, ) points, not contributing to optical conductivity.

Abstract

Polarized electronic Raman scattering from the NCCO superconductor at optimal electron doping (T_c=22 K) reveals the formation of an anisotropic pseudogap below a characteristic temperature T* ~ 220 K and energy E*_g = 850 cm-1. Below T* a pronounced suppression of the incoherent spectral weight below E*_g in the nodal directions of k-space is observed. This is concomitant with the emergence of long-lived excitations in the vicinity of the (\pi/2, \pi/2) points that do not contribute to the optical conductivity.