强关联电荷转移绝缘体中的超导邻近效应
Superconducting proximity effect in a strongly correlated charge-transfer insulator
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中文总结 AI 辅助
研究强关联电荷转移绝缘体中的超导邻近效应，利用超低温STM构建单层H/T-NbSe2横向结，在不同耦合区研究其超导能隙及束缚态，确立该横向结为阐明超导邻近效应的模型平台。
中文摘要 AI 辅助
强关联绝缘体中的邻近诱导超导为工程化具有定制功能的量子态物质和人工系统提供了一条通用途径。然而，超导与关联绝缘态之间的微观相互作用仍知之甚少。本文利用超低温扫描隧道显微镜（STM）系统研究了电荷转移绝缘体中的超导邻近效应。通过STM针尖操纵，构建了由超导单层H-NbSe2和电荷转移绝缘单层T-NbSe2组成的原子级尖锐横向结，可直接进入可调耦合区。在弱耦合区，T-NbSe2中存在由邻近效应诱导的稳健超导能隙，相对于H-NbSe2能隙值减小。进入强耦合区后，T-NbSe2展现出与H-NbSe2相当的超导能隙，并伴有明显的粒子-空穴对称的能隙内束缚态，与类汤浅-芝-鲁西诺夫激发一致。这些发现将单层H/T-NbSe2横向结确立为阐明强关联电荷转移绝缘体中超导邻近效应的模型平台。
英文摘要
Proximity-induced superconductivity in strongly correlated insulators provides a versatile route for engineering quantum states of matter and artificial systems with tailored functionalities. However, microscopic interplay between superconductivity and correlated insulating states remains poorly understood. Here we use ultralow-temperature scanning tunnelling microscopy (STM) to systemically investigate superconducting proximity effects in a charge-transfer insulator. Via STM tip manipulation, atomically sharp lateral junctions composed of superconducting monolayer H-NbSe2 and charge-transfer insulating monolayer T-NbSe2 are constructed, enabling direct access to tunable coupling regimes. In the weak-coupling regime, there is a robust proximity-induced superconducting gap in T-NbSe2, with a reduced gap value relative to that of H-NbSe2. Upon entering the strong-coupling regime, T-NbSe2 exhibits a superconducting gap comparable to that of H-NbSe2, accompanied by pronounced particle-hole-symmetric in-gap bound states, consistent with Yu-Shiba-Rusinov-like excitations. These findings establish monolayer H/T-NbSe2 lateral junctions as a model platform for elucidating superconducting proximity effects in strongly correlated charge-transfer insulators.
