Superconductivity originates from the coupling between charge carriers and bosonic excitations of either phononic or electronic origin. Identifying the most relevant pairing glue is a key step towards a clear understanding of the unconventional superconductivity. Here, by applying the ultrafast optical spectroscopy on the electron-doped cuprates La1.9Ce0.1CuO4±δ, we discern a bosonic mode of electronic origin that has the strongest coupling with the charge carriers near Tc. We argue that this mode is associated with the two-dimensional antiferromagnetic spin fluctuations, and can fully account for the superconducting pairing. Our work may help to establish a quantitative relation between bosonic excitations and superconducting pairing in electron-doped cuprates, and pave the way for systematic exploration of superconductivity and other collective phenomena in all correlated materials.
@article{arxiv.1602.06669,
title = {Bosonic excitations and electron pairing in an electron-doped cuprate superconductor},
author = {M. C. Wang and H. S. Yu and Y. -F. Yang and S. N. Luo and J. Xiong and K. Jin and J. Qi},
journal= {arXiv preprint arXiv:1602.06669},
year = {2018}
}