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arXiv 0710.5555cond-mat.supr-concond-mat.dis-nn
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无序超导体中超导体-绝缘体转变的性质

Nature of the superconductor-insulator transition in disordered superconductors

Yonatan Dubi, Yigal Meir, Yshai Avishai

摘要:

当超导薄膜变得无序并受到增加的磁场的作用时,当它经历从超导状态到绝缘状态的转变时达到一个点。我们使用Bogoliubov-De-Gennes方程和一种新的蒙特卡罗方法来研究这种转变的数值,从微观哈密顿量。无序的关键效应是创造出强超导性的“岛”,与只有弱超导性的区域相耦合。在弱无序的情况下,增加的磁场最终会破坏整个材料的超导状态,导致绝缘体。另一方面,当无序很强时,超导性在岛中持续存在,磁场的作用是抑制它们之间的耦合,导致强烈的超导相位波动,再次导致绝缘状态。这些发现可能与高温超导体有关,其中内在无序可能起作用。

英文摘要:

As a superconducting thin film becomes disordered and subject to an increasing magnetic field, a point is reached when it undergoes a transition from a superconducting to an insulating state. We use the Bogoliubov-De-Gennes equations and a novel Monte-Carlo approach to study this transition numerically, starting from a microscopic hamiltonian. The key effect of disorder is to create 'islands' of strong superconductivity, coupled by regions that are only weakly superconducting. In the case of weak disorder, an increasing magnetic field eventually destroys the superconducting state throughout the material, leading to an insulator. On the other hand, when disorder is strong, superconductivity persists in the islands, and the effect of a magnetic field is to suppress the coupling between them, resulting in strong superconducting phase fluctuations, again leading to an insulating state. These findings may be relevant to the high-temperature superconductors, where intrinsic disorder may play a role.

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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