Superconductivity and strong correlations in moire flat bands
Superconductivity and strong correlations in moire flat bands
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DOI：
10.1038/s41567-020-0906-9
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发表时间：
2020-05-19
期刊：
影响因子：
19.6
通讯作者：
Young, Andrea F.
中科院分区：
文献类型：
--
作者：
Balents, Leon;Dean, Cory R.;Young, Andrea F.
强相关系统可以产生壮观的现象学，从高温超导到以长程量子纠缠为特征的物质状态的出现。低密度平带系统发挥着至关重要的作用，因为能带的能量范围非常窄，以至于库仑相互作用主导了动能，使这些材料处于强相关状态。实验上，当一个能带的能量和动量都很窄时，它的填充可以在整个范围内原位调整，从空到满。最近，一种特殊的平带系统——范德华异质结构，例如扭曲双层石墨烯——表现出强相关态和超导性，但仍不清楚两者之间的联系程度。在这里，我们回顾了范德华异质结构平带工程的现状和前景，并探讨了这两种现象如何从莫尔平带中出现。扭曲双层二维材料中超导性和强相互作用的识别引发了有关这些现象相互作用的许多问题。本视角介绍了该领域的现状和未来研究的紧迫问题。
Strongly correlated systems can give rise to spectacular phenomenology, from high-temperature superconductivity to the emergence of states of matter characterized by long-range quantum entanglement. Low-density flat-band systems play a vital role because the energy range of the band is so narrow that the Coulomb interactions dominate over kinetic energy, putting these materials in the strongly-correlated regime. Experimentally, when a band is narrow in both energy and momentum, its filling may be tuned in situ across the whole range, from empty to full. Recently, one particular flat-band system-that of van der Waals heterostructures, such as twisted bilayer graphene-has exhibited strongly correlated states and superconductivity, but it is still not clear to what extent the two are linked. Here, we review the status and prospects for flat-band engineering in van der Waals heterostructures and explore how both phenomena emerge from the moire flat bands.The identification of superconductivity and strong interactions in twisted bilayer 2D materials prompted many questions about the interplay of these phenomena. This Perspective presents the status of the field and the urgent issues for future study.