Kushwaha S K, Krizan J W, Xiong J, Klimczuk T, Gibson Q D, Liang T, Ong N P, Cava R J
Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
J Phys Condens Matter. 2014 May 28;26(21):212201. doi: 10.1088/0953-8984/26/21/212201. Epub 2014 May 8.
Resistivity, dc magnetization, and heat capacity measurements are reported for superconducting NaBi. T(c), the electronic contribution to the specific heat γ, the ΔC(p)/γT(c) ratio, and the Debye temperature are found to be 2.15 K, 3.4 mJ mol(-1) K(-2), 0.78, and 140 K respectively. The calculated electron-phonon coupling constant (λ(ep) = 0.62) implies that NaBi is a moderately coupled superconductor. The upper critical field and coherence length are found to be 250 Oe and 115 nm, respectively. Electronic structure calculations show NaBi to be a good metal, in agreement with the experiments; the p(x) and p(y) orbitals of Bi dominate the electronic states at the Fermi Energy.
报道了超导NaBi的电阻率、直流磁化强度和热容测量结果。发现超导转变温度T(c)、电子比热系数γ、ΔC(p)/γT(c)比值和德拜温度分别为2.15 K、3.4 mJ mol⁻¹ K⁻²、0.78和140 K。计算得到的电子-声子耦合常数（λ(ep) = 0.62）表明NaBi是一种中等耦合的超导体。发现上临界场和相干长度分别为250 Oe和115 nm。电子结构计算表明NaBi是一种良金属，与实验结果一致；Bi的p(x)和p(y)轨道在费米能处主导电子态。
