We report the discovery of bulk superconductivity (SC) at 6.1 K in a quasi-one-dimensional (Q1D) chromium pnictide K2Cr3As3 which contains [(Cr3As3)2−]∞ double-walled subnano-tubes with face-sharing Cr6/2 (As6/2) octahedron linear chains in the inner (outer) wall. The material has a large electronic specific-heat coefficient of 70∼75 mJ K−2 mol−1, indicating significantly strong electron correlations. Signature of non-Fermi liquid behavior is shown by the linear temperature dependence of resistivity in a broad temperature range from 7 to 300 K. Unconventional SC is preliminarily manifested by the estimated upper critical field exceeding the Pauli limit by a factor of three to four. The title compound represents a rare example that possibly unconventional SC emerges in a Q1D system with strong electron correlations.
@article{arxiv.1412.0067,
title = {Superconductivity in quasi-one-dimensional K$_2$Cr$_3$As$_3$ with significant electron correlations},
author = {Jin-Ke Bao and Ji-Yong Liu and Cong-Wei Ma and Zhi-Hao Meng and Zhang-Tu Tang and Yun-Lei Sun and Hui-Fei Zhai and Hao Jiang and Hua Bai and Chun-Mu Feng and Zhu-An Xu and Guang-Han Cao},
journal= {arXiv preprint arXiv:1412.0067},
year = {2015}
}