Single- and two-particle energy gaps across the disorder-driven superconductor-insulator transition
Single- and two-particle energy gaps across the disorder-driven superconductor-insulator transition
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DOI：
10.1038/nphys2037
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发表时间：
2011-11-01
期刊：
影响因子：
19.6
通讯作者：
Trivedi, Nandini
中科院分区：
文献类型：
--
作者：
Bouadim, Karim;Loh, Yen Lee;Trivedi, Nandini
超导性和局域化之间的竞争在凝聚态物理学中提出了深刻的问题。尽管经过几十年的研究，超导体-绝缘体转变的机制和绝缘体的性质仍然不清楚。我们使用量子蒙特卡罗模拟，治疗，在平等的基础上，不均匀的振幅变化和相位波动，比以前的理论的一个重大进步。我们获得了新的微观见解，并为本地光谱探针进行了可测试的预测。态密度中的能隙在整个跃迁中存在，但相干峰只存在于超导体中。与传统理论相反，在临界无序和临界温度以上，一个特征性的赝能隙仍然存在。令人惊讶的是，绝缘体具有两个粒子的间隙尺度，在超导体-绝缘体过渡时消失，尽管有一个强大的单粒子间隙。
The competition between superconductivity and localization raises profound questions in condensed-matter physics. In spite of decades of research, the mechanism of the superconductor-insulator transition and the nature of the insulator are not understood. We use quantum Monte Carlo simulations that treat, on an equal footing, inhomogeneous amplitude variations and phase fluctuations, a major advance over previous theories. We gain new microscopic insights and make testable predictions for local spectroscopic probes. The energy gap in the density of states survives across the transition, but coherence peaks exist only in the superconductor. A characteristic pseudogap persists above the critical disorder and critical temperature, in contrast to conventional theories. Surprisingly, the insulator has a two-particle gap scale that vanishes at the superconductor-insulator transition, despite a robust single-particle gap.