具有增强超导性的kagome超导体CsV$_{3-x}$Ta$_x$Sb$_5$中独特的范霍夫奇点
超导电性
2023-07-04 v1 材料科学
强关联电子
摘要
范霍夫奇点(VHS)被视为非常规超导性的驱动源。二维(2D)材料中的VHS由连接类电子与类空穴能带的鞍点构成。在罕见情形下,当VHS出现在费米能级时,类电子与类空穴导电可共存,从而产生增强的态密度以及用于非常规电子配对的库仑相互作用吸引分量。然而,该范霍夫图景常因化学势不当或竞争不稳定性而被破坏。此处,我们利用角分辨光电子能谱测量,报道了在kagome超导体CsVTaSb(x~0.4)中观测到与费米能级完美对齐的VHS,该材料在所有当前AVSb(A=Cs, Rb, K)变体中常压下实现了创纪录的高超导转变温度。依赖掺杂的测量揭示了范霍夫图景在提升超导性中的重要作用,而谱成像扫描隧道显微镜测量表明该体系中存在着独特的超导态。
引用
@article{arxiv.2307.01042,
title = {A unique van Hove singularity in kagome superconductor CsV$_{3-x}$Ta$_x$Sb$_5$ with enhanced superconductivity},
author = {Yang Luo and Yulei Han and Jinjin Liu and Hui Chen and Zihao Huang and Linwei Huai and Hongyu Li and Bingqian Wang and Jianchang Shen and Shuhan Ding and Zeyu Li and Shuting Peng and Zhiyuan Wei and Yu Miao and Xiupeng Sun and Zhipeng Ou and Ziji Xiang and Makoto Hashimoto and Donghui Lu and Yugui Yao and Haitao Yang and Xianhui Chen and Hong-Jun Gao and Zhenhua Qiao and Zhiwei Wang and Junfeng He},
journal= {arXiv preprint arXiv:2307.01042},
year = {2023}
}
备注
20 pages, 4 figures