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arXiv 1312.2602cond-mat.str-elcond-mat.mes-hallcond-mat.supr-con
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超导体隧穿局域态的非平衡理论

Non-equilibrium theory of tunneling into localized state in superconductor

Ivar Martin, Dmitry Mozyrsky

摘要:

在完全带隙超导体中,单个静磁杂质导致带隙内准粒子束缚态的形成。在远低于超导转变的温度下,状态的能量弛豫和自旋退相预计将被指数抑制。这种状态的存在可以在电子隧穿实验中被检测为在正偏压和负偏压下的一对电导峰。在这里,我们表明,对于一个任意弱的隧穿强度,峰值必须是对称的相对于所施加的偏压。这与标准结果相反,标准结果是隧穿电导正比于局域态密度(通常是粒子-空穴不对称的)。如果允许杂质态的有限密度,或者杂质耦合到另一个非超导平衡浴,则可以恢复不对称性。

英文摘要:

A single static magnetic impurity in a fully-gapped superconductor leads to formation of an intragap quasiparticle bound state. At temperatures much below the superconducting transition, the energy relaxation and spin dephasing of the state are expected to be exponentially suppressed. The presence of such a state can be detected in electron tunneling experiments as a pair of conductance peaks at positive and negative biases. Here we show, that for an arbitrarily weak tunneling strength, the peaks have to be symmetric with respect to the applied bias. This is in contrast to the standard result that the tunneling conductance is proportional to the local (in general particle-hole asymmetric) density of states. The asymmetry can be recovered is one allows for either a finite density of impurity states, or that impurities are coupled to another, non-superconducting, equilibrium bath.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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