Bag Biplab, Loke Rajendra, Singh Birender, Thamizhavel A, Singh Bahadur, Ramakrishnan S
Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400005, India.
J Phys Condens Matter. 2022 Mar 8;34(19). doi: 10.1088/1361-648X/ac5651.
We report superconducting state properties and electronic structure of a full Heusler material ScAuAl. The resistivity measurement indicates a zero-field (at nominal Earth's field) superconducting transition temperature,= 5.12 K (in contrary to the previously reported value of 4.4 K), which falls in the highest-regime among the Heusler superconductors. The magnetization data shows that ScAuAl is a moderate type-II superconductor, where the critical field values can be estimated from the Ginzburg-Landau-Abrikosov-Gorkov theory. The field-dependent magnetization response further shows signatures of flux jump in ScAuAl. A sharp jump in the temperature dependent specific heat () data confirms bulk superconductivity. We report that the electron-phonon coupling constant,= 0.77, suggesting a moderate electron-phonon coupling in ScAuAl. Further, we show that the observedvalue in ScAuAl is the highest amongst the reported Heusler superconductors, indicating strong correlation betweenandvalues and significant role of electron-phonon coupling in mediating superconductivity in Heusler superconductors. Finally, we discuss the electronic properties and reveal the existence of van Hove singularity near the Fermi level in ScAuAl.
我们报告了全赫斯勒材料ScAuAl的超导态特性和电子结构。电阻率测量表明，零场（在标称地磁场）超导转变温度(T_c = 5.12) K（与先前报道的4.4 K值相反），这处于赫斯勒超导体中的最高范围。磁化数据表明ScAuAl是一种中等类型的II型超导体，其临界场值可根据金兹堡 - 朗道 - 阿布里科索夫 - 戈尔科夫理论估算。场依赖的磁化响应进一步显示了ScAuAl中磁通跳跃的特征。温度依赖的比热（(C/T)）数据中的急剧跳跃证实了体超导性。我们报告电子 - 声子耦合常数(\lambda = 0.77)，表明ScAuAl中存在中等的电子 - 声子耦合。此外，我们表明在ScAuAl中观察到的(T_c)值在报道的赫斯勒超导体中是最高的，这表明(T_c)和(\lambda)值之间存在强相关性，并且电子 - 声子耦合在介导赫斯勒超导体中的超导性方面起着重要作用。最后，我们讨论了电子性质并揭示了ScAuAl中费米能级附近存在范霍夫奇点。
