Specific heat and electronic states of superconducting boron-doped silicon carbide
Specific heat and electronic states of superconducting boron-doped silicon carbide
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DOI：
10.1103/physrevb.78.024517
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发表时间：
2008-03
影响因子：
3.7
通讯作者：
M. Kriener;Y. Maeno;T. Oguchi;Z. Ren;J. Kato;T. Muranaka;J. Akimitsu
中科院分区：
文献类型：
--
作者：
M. Kriener;Y. Maeno;T. Oguchi;Z. Ren;J. Kato;T. Muranaka;J. Akimitsu
2004年重硼掺杂半导体金刚石（C:B）和2006年重硼掺杂半导体硅（Si:B）中超导性的发现，重新引起了人们对掺杂半导体超导态物理学的兴趣。最近，我们在密切相关的重硼掺杂碳化硅（SiC:B）“混合”体系中发现了超导性。有趣的是，后一种化合物是i型超导体，而上述两种材料是ii型超导体。在本文中，我们对我们最近的比热研究，以及能带结构和预期的费米表面进行了广泛的分析。我们观察到超导状态下的电子比热与温度有明显的二次关系。可能的原因是节点间隙结构或由于样品的非超导部分造成的剩余态密度。在金兹堡-朗道框架中估计了基本超导参数。我们比较和讨论我们的结果与报告的C:B和Si:B。最后，我们评论了SiC:B与两种“母体”材料C:B和Si:B相比超导性差异的可能来源。
The discoveries of superconductivity in the heavily-boron doped semiconductors diamond (C:B) in 2004 and silicon (Si:B) in 2006 have renewed the interest in the physics of the superconducting state of doped semiconductors. Recently, we discovered superconductivity in the closely related ''mixed'' system heavily boron-doped silcon carbide (SiC:B). Interestingly, the latter compound is a type-I superconductor whereas the two aforementioned materials are type-II. In this paper we present an extensive analysis of our recent specific-heat study, as well as the band structure and expected Fermi surfaces. We observe an apparent quadratic temperature dependence of the electronic specific heat in the superconducting state. Possible reasons are a nodal gap structure or a residual density of states due to non-superconducting parts of the sample. The basic superconducting parameters are estimated in a Ginzburg-Landau framework. We compare and discuss our results with those reported for C:B and Si:B. Finally, we comment on possible origins of the difference in the superconductivity of SiC:B compared to the two ''parent'' materials C:B and Si:B.