Meissner Effect of Dirac Electrons in Superconducting State Due to Inter-Band Effect
Meissner Effect of Dirac Electrons in Superconducting State Due to Inter-Band Effect
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DOI：
10.7566/jpsj.84.084704
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发表时间：
2015-02
影响因子：
1.7
通讯作者：
T. Mizoguchi;M. Ogata
中科院分区：
文献类型：
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作者：
T. Mizoguchi;M. Ogata
固体中的狄拉克电子由于其线性色散关系和双带性质而显示出特有的物理性质。尽管人们对正常态狄拉克电子的输运现象进行了深入的研究，但对超导态狄拉克电子的输运现象还没有完全了解。特别是，尚不清楚狄拉克电子在超导状态下是否表现出迈斯纳效应（ME），因为线性色散的结果是不存在电流算符的抗磁项。本文从Kubo公式出发，研究了超导态三维重Dirac电子的ME，阐明了Meissner核在带间贡献的作用下是有限的.狄拉克电子的这种ME机制与一般金属中电子的ME机制完全不同。结果表明，即使超导能隙为零，迈斯纳核仍然是有限的。这是狄拉克电子系统中一个不可避免的问题。
Dirac electrons in solids show characteristic physical properties due to their linear dispersion relation and two-band nature. Although the transport phenomena of Dirac electrons in a normal state have intensively been studied, the transport phenomena in a superconducting state have not been fully understood. In particular, it is not clear whether Dirac electrons in a superconducting state show Meissner effect (ME), since a diamagnetic term of a current operator is absent as a result of the linear dispersion. We investigate the ME of three dimensional massive Dirac electrons in a superconducting state on the basis of Kubo formula, and clarify that Meissner kernel becomes finite by use of the inter-band contribution. This mechanism of the ME for Dirac electrons is completely different from that for the electrons in usual metals. Our result shows that the Meissner kernel remains finite even when the superconducting gap vanishes. This is an unavoidable problem in the Dirac electron system as reported in the ...