Xu Ke-Jun, He Junfeng, Chen Su-Di, He Yu, Abadi Sebastien N, Rotundu Costel R, Lee Young S, Lu Dong-Hui, Guo Qinda, Tjernberg Oscar, Devereaux Thomas P, Lee Dung-Hai, Hashimoto Makoto, Shen Zhi-Xun
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA.
Science. 2024 Aug 16;385(6710):796-800. doi: 10.1126/science.adk4792. Epub 2024 Aug 15.
In the underdoped n-type cuprate NdCeCuO, long-range antiferromagnetic order reconstructs the Fermi surface, resulting in a putative antiferromagnetic metal with small Fermi pockets. Using angle-resolved photoemission spectroscopy, we observe an anomalous energy gap, an order of magnitude smaller than the antiferromagnetic gap, in a wide portion of the underdoped regime and smoothly connecting to the superconducting gap at optimal doping. After 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 those of the p-type cuprates.
在欠掺杂的n型铜酸盐NdCeCuO中，长程反铁磁序重构了费米面，形成了一种具有小费米口袋的假定反铁磁金属。利用角分辨光电子能谱，我们在欠掺杂区域的很大一部分中观察到一个异常能隙，其大小比反铁磁能隙小一个数量级，并在最佳掺杂时平滑地连接到超导能隙。在结合相图考虑所有已知的有序倾向后，我们推测欠掺杂n型铜酸盐中的正常态能隙源于库珀对。正常态能隙的高温标度为在n型铜酸盐中设计出与p型铜酸盐相当的更高转变温度带来了希望。
