文档介绍：
层状铁基超导体的 Ginzburg-Landau 方程#
赵静翔,顾强**
(北京科技大学物理系,北京 100083)
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摘要:基于铁基超导体的多带能隙特征,采用两带模型,假设带内电子配对为各项同性,带
间电子配对序参量为扩展的 s 波形式。利用 Gro'kov 理论,推导了层状铁基超导体的二维
Ginzburg-Landau 方程,并给出了自由能密度和垂直于二维载流子运动平面的上临界场表达
,上临界场在转变温度附近随温度变化的曲线呈对数形,该特征与最近的一些
实验结果相符合,并且与三维体系的上临界场有显著不同,这一特点是由系统的准二维特征
所决定.
关键词:铁基超导体,Ginzburg-Landau 方程,上临界场
中图分类号:7420D, 7470J
Ginzburg-Landau Equation of layered iron-based
superconductor
Zhao Jingxiang, Gu Qiang
(Department of Physics, University of Science and Technology Beijing; Beijing
100083)
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Abstract: Based on the multi-gap of the iron-based superconductors, we use the two-band model
to obtain the two-dimensional Ginzburg-Landau Equations with Gro'kov’s method. The free
energy density and the upper critical field are also presented. The calculation suggests that the
dependence of the upper critical field on temperature is logarithmic. Our results are consistent
with some experiments, and are different from three-dimensional materials. These are believed to
be the characteristic properties of quasi two-dimensional systems.
Key words:
Iron-based superconductor, Ginzburg-Landau Equations, Upper critical field
0 引言
铁基超导体因其较高的转变温度和较强的上临界磁场,成为超导物理领域的研究热点之
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[1-3],其载流子运动集中在 FeSe 或者 FeAs 面上,呈现准二维形
式,因此,,可以把铁基
超导体分成 FeSe 和 FeAs , FeSe 类超导材料的载流子为电子,配对形式
为常规 s 波[4