Materials Research Express ( IF 2.3 ) Pub Date : 2020-11-05 , DOI: 10.1088/2053-1591/abc4b3 W Wu 1, 2 , Y J Li 1, 2 , J H Zhang 1, 2 , Z H Yu 3 , Z Y Liu 1, 2 , P Zheng 1, 2 , H X Yang 1, 2 , C Dong 1, 2, 4 , K Liu 5 , T Xiang 1, 2, 6 , J L Luo 1, 2, 4
Exploration of superconductivity in light element compounds has drawn considerable attention because those materials can easily realize the high T C superconductivity, such as LnNi2B2C (T C=17 K), MgB2 (T C=39 K), and very recently super-hydrides under pressure (T C=250 K). Here we report the discovery of bulk superconductivity at 7.8 K in scandium borocarbide Sc20BC27 with a tetragonal lattice which structure changes based on the compound of Sc3C4 with very little B doping. Magnetization and specific heat measurements show bulk superconductivity. An upper critical field of H c2(0)∼8 T is determined. Low temperature specific-heat shows that this system is a BCS fully gapped s-wave superconductor. Electronic structure calculations demonstrate that compared with Sc3C4 there are more orbital overlap and hybridization between Sc 3d electrons and 2p electrons of C-C(B)-C fragment in Sc20BC27, which form a new electric conduction path of Sc-C(B)-Sc. Those changes influence the band structure at the Fermi level and may be the reason of superconductivity in Sc20BC27.
中文翻译:
硼杂化scan轨道杂交的超导性
轻元素化合物中超导性的探索引起了极大的关注,因为这些材料可以轻松实现高T C超导性,例如LnNi 2 B 2 C(T C = 17 K),MgB 2(T C = 39 K)以及非常高的导电性。最近在压力下超氢化物(T C = 250 K)。在这里,我们报道了在具有四方晶格的硼碳化carb Sc 20 BC 27中在7.8 K时发现体超导的发现,该结构基于Sc 3 C 4的化合物而改变很少的B掺杂。磁化和比热测量显示出整体超导性。确定H c2(0)〜8 T的上限临界场。低温比热表明,该系统是BCS全隙缝s波超导体。电子结构计算表明,与Sc 3 C 4相比,Sc 20 BC 27中CC(B)-C片段的Sc 3 d电子和2 p电子之间存在更多的轨道重叠和杂化,形成了Sc的新导电路径-C(B)-Sc。这些变化影响费米能级的能带结构,可能是Sc 20 BC超导的原因27。