In the underdoped n-type cuprate Nd2-xCexCuO4, long-ranged antiferromagnetic order reconstructs the Fermi surface, resulting in a putative antiferromagnetic metal with small pockets. Using angle-resolved photoemission spectroscopy, we observe an anomalous energy gap, an order of magnitude smaller than the antiferromagnetic gap, in a wide range of the underdoped regime and smoothly connecting to the superconducting gap at optimal doping. After carefully considering all the known ordering tendencies in tandem with the phase diagram, we hypothesize that the normal state gap in the underdoped n-type cuprates originates from Cooper pairing. The high temperature scale of the normal state gap raises the prospect of engineering higher transition temperatures in the n-type cuprates comparable to that of the p-type cuprates.
@article{arxiv.2309.10208,
title = {Anomalous normal state gap in an electron-doped cuprate},
author = {Ke-Jun Xu and Junfeng He and Su-Di Chen and Yu He and Sebastien N. Abadi and Costel. R. Rotundu and Young S. Lee and Dong-Hui Lu and Qinda Guo and Oscar Tjernberg and Thomas P. Devereaux and Dung-Hai Lee and Makoto Hashimoto and Zhi-Xun Shen},
journal= {arXiv preprint arXiv:2309.10208},
year = {2024}
}