A New Superconductor Parent Compound NaMn_6Bi_5 with Quasi-One-Dimensional Structure and Lower Antiferromagnetic-Like Transition Temperatures

Mn-based superconductors are very rare and their superconductivity has only been reported in three-dimensional MnP and quasi-one-dimensional KMn_6Bi_5 and RbMn_6Bi_5 with Mn_6Bi_5^- columns under high pressures. Here we report the synthesis, magnetism, electrical resistivity, and specific heat capacity of the newly discovered quasi-one-dimensional NaMn_6Bi_5. Compared with other AMn_6Bi_5 (A = K, Rb, and Cs), NaMn_6Bi_5 has abnormal Bi–Bi bond lengths and two antiferromagnetic-like transitions at 47.3 K and 51.8 K. Anisotropic resistivity and low-temperature non-Fermi liquid behavior are observed. Heat capacity measurement reveals that the Sommerfeld coefficient for NaMn_6Bi_5 is unusually large. Using first-principles calculations, an unusual enhancement of density of states near the Fermi level is demonstrated for NaMn_6Bi_5. The features make NaMn_6Bi_5 a more suitable platform to explore the interplay of magnetism and superconductivity.