论文标题
超导线节点金属casb $ _2 $的准2D费米表面
Quasi-2D Fermi surface of superconducting line-nodal metal CaSb$_2$
论文作者
论文摘要
我们报告CASB $ _2 $单晶的费米表面和超导参数（超过$ t _ {\ text {c}} \ sim 1.8〜 \ text {k} $）由自弹方法生长。 De-Haas-Van-Alphen和Shubnikov-De-Haas振荡的频率证明了准二维（Quasi-2d）费米表面的频率，这与构成由第一强度计算预测的DIRAC线的费米表面之一。超导状态的测量结果表明，CASB $ _2 $接近I型超导体，带有Ginzburg-landau（GL）参数的统一参数。上临界场$ h _ {\ text {c2}} $的温度依赖性由一个模型很好地描述，考虑了两个超导频带，以及从$ h _ {\ text {c2}}}（0〜 \ text {k}）估计的有效质量的增强与QUASI-2频段一致。我们的结果表明，形成狄拉克线的准2D频段有助于CASB $ _2 $中的超导性。
We report on the Fermi surfaces and superconducting parameters of CaSb$_2$ single crystals (superconducting below $T_{\text{c}}\sim 1.8~\text{K}$) grown by the self-flux method. The frequency of de-Haas-van-Alphen and Shubnikov-de-Haas oscillations evidences a quasi-two-dimensional (quasi-2D) Fermi surface, consistent with one of the Fermi surfaces forming Dirac lines predicted by first-principles calculations. Measurements in the superconducting state reveal that CaSb$_2$ is close to a type-I superconductor with the Ginzburg-Landau (GL) parameter of around unity. The temperature dependence of the upper critical field $H_{\text{c2}}$ is well described by a model considering two superconducting bands, and the enhancement of the effective mass estimated from $H_{\text{c2}}(0~\text{K})$ is consistent with the quasi-2D band observed by the quantum oscillations. Our results indicate that a quasi-2D band forming Dirac lines contributes to the superconductivity in CaSb$_2$.
