Mo6Ga31 endohedral cluster superconductor
Mo6Ga31 endohedral cluster superconductor
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DOI：
10.1016/j.jallcom.2020.156400
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发表时间：
2020-04
影响因子：
6.2
通讯作者：
V. Verchenko;A. Zubtsovskii;A. Tsirlin;Zheng Wei;M. Roslova;E. Dikarev;A. Shevelkov
中科院分区：
文献类型：
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作者：
V. Verchenko;A. Zubtsovskii;A. Tsirlin;Zheng Wei;M. Roslova;E. Dikarev;A. Shevelkov
内禀团簇化合物是一种新型超导体的丰富来源，具有强耦合区和多能隙超导等重要性质。在这里，我们报告的合成，晶体结构和电子结构，和物理性质的Mo 6 Ga 31内面团簇超导体。该化合物具有两种晶体学变体，单斜和三斜，这是由Mo@ Ga 10内面簇构建的。这两种结构具有定性相同的电子态密度，在费米能级处显示出高峰。由于三斜畴和单斜畴之间的邻近效应，在零磁场下，Mo 6 Ga 31块材在8.2K的临界温度下表现出单一的超导转变。上临界场，这是7.8 T在零温度下，显示出明显的增强相对于Werthamer-Helfand-Honenberg预测。因此，热容量测量表明，在超导状态下存在强的电子-声子耦合，其比值为2 Δ（0）/（k B T c）= 4.5，其中2 Δ（0）= 3.2 meV是零温度下的完整超导能隙。
Endohedral cluster compounds are a rich source of new superconductors, where nontrivial properties are expected, including strong coupling regime and multigap superconductivity. Here, we report on the synthesis, crystal and electronic structure, and physical properties of the Mo 6 Ga 31 endohedral cluster superconductor. The compound has two crystallographic modifications, monoclinic and triclinic, which are built by the Mo@ Ga 10 endohedral clusters. Both structures possess qualitatively the same electronic density of states showing a high peak at the Fermi level. Due to the proximity effect of the triclinic and monoclinic domains, which are in the strong contact with each other, bulk Mo 6 Ga 31 exhibits single superconducting transition at the critical temperature of 8.2 K in zero magnetic field. The upper critical field, which is 7.8 T at zero temperature, shows clear enhancement with respect to the Werthamer-Helfand-Honenberg prediction. Accordingly, heat capacity measurements indicate strong electron-phonon coupling in the superconducting state with the large ratio of 2 Δ (0)/(k B T c)= 4.5, where 2 Δ (0)= 3.2 meV is the full superconducting gap at zero temperature.