Signature of coexistence of superconductivity and ferromagnetism in two-dimensional NbSe₂ triggered by surface molecular adsorption

Authors

Xiaojiao Zhu, University of Science and Technology of China
Yuqiao Guo, University of Science and Technology of China
Hao Cheng, University of Science and Technology of China
Jun Dai, University of Nebraska- Lincoln
Xingda An, University of Science and Technology of China
Jiyin Zhao, University of Science and Technology of China
Kangzhen Tian, University of Science and Technology of China
Shiqiang Wei, University of Science and Technology of ChinaFollow
Xiao Cheng Zeng, University of Nebraska-LincolnFollow
Changzheng Wu, University of Science and Technology of ChinaFollow
Yi Xie, University of Science and Technology of China

Document Type

Article

Date of this Version

2016

Citation

NATURE COMMUNICATIONS | 7:11210 | DOI: 10.1038/ncomms11210 |www.nature.com/naturecommunications

Comments

This work is licensed under a Creative Commons Attribution 4.0 International License

Abstract

Ferromagnetism is usually deemed incompatible with superconductivity. Consequently, the coexistence of superconductivity and ferromagnetism is usually observed only in elegantly designed multi-ingredient structures in which the two competing electronic states originate from separate structural components. Here we report the use of surface molecular adsorption to induce ferromagnetism in two-dimensional superconducting NbSe₂, representing the freestanding case of the coexistence of superconductivity and ferromagnetism in one two-dimensional nanomaterial. Surface-structural modulation of the ultrathin superconducting NbSe₂ by polar reductive hydrazine molecules triggers a slight elongation of the covalent Nb–Se bond, which weakens the covalent interaction and enhances the ionicity of the tetravalent Nb with unpaired electrons, yielding ferromagnetic ordering. The induced ferromagnetic momentum couples with conduction electrons generating unique correlated effects of intrinsic negative magnetoresistance and the Kondo effect. We anticipate that the surface molecular adsorption will be a powerful tool to regulate spin ordering in the two-dimensional paradigm.