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Superconductivity in quasi-one-dimensional Cs2Cr3As3 with large interchain distance

Since the discovery of high-temperature superconductivity (SC) in quasi-two-dimensional copper oxides, a few layered compounds, which bear similarities to the cuprates, have also been found to host unconventional SC. Our recent observation of SC at 6.1 K in correlated electron material K2Cr3As3 (J. K. Bao et al., arXiv: 1412.0067) represents an obviously different paradigm, primarily because of its quasi-one-dimensional (Q1D) nature. The new material is structurally featured by the (Cr3As3)2- double-walled subnano-tubes composed of face-sharing Cr6/2 (As6/2) octahedron linear chains, which are well separated by columns of K+ counterions. Later, an isostructural superconducting Rb2Cr3As3 was synthesized, thus forming a new superconducting family. Here we report the third member, Cs2Cr3As3, which possesses the largest interchain distance. SC appears below 2.2 K. Similar to the former two sister compounds, Cs2Cr3As3 exhibits a non-Fermi liquid behavior with a linear temperature dependence of resistivity in the normal state, and a high upper critical field beyond the Pauli limit as well, suggesting common unconventional SC in the Q1D Cr-based material.