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arXiv 2302.00686cond-mat.mes-hallcond-mat.str-elcond-mat.supr-con
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可调谐莫尔准周期晶体中的超导性与强相互作用

Superconductivity and strong interactions in a tunable moiré quasiperiodic crystal

Aviram Uri, Sergio C. de la Barrera, Mallika T. Randeria, Daniel Rodan-Legrain, Trithep Devakul, Philip J. D. Crowley, Nisarga Paul, Kenji Watanabe, Takashi Tan… 展开作者

Aviram Uri, Sergio C. de la Barrera, Mallika T. Randeria, Daniel Rodan-Legrain, Trithep Devakul, Philip J. D. Crowley, Nisarga Paul, Kenji Watanabe, Takashi Taniguchi, Ron Lifshitz, Liang Fu, Raymond C. Ashoori, Pablo Jarillo-Herrero

AI总结:

本文提出一种由三层石墨烯以两个不同扭转角组装而成的可调谐莫尔准周期晶体,在其中观测到超导性及味对称性破缺相变附近的强电子相互作用,为研究强关联准周期量子材料提供了新平台。

摘要:

准周期晶体中的电子态通常无法用布洛赫描述,这使得它们既迷人又神秘。由于其复杂性和相对稀缺性,与周期性和非晶结构相比,准周期晶体的研究尚不充分。在此,我们引入一种新型的高度可调谐准周期晶体,它可以由周期性组件轻松组装而成。通过以两个不同的扭转角扭转三层石墨烯,我们形成了两个具有不可公度莫尔原胞的莫尔图案。与许多在原子尺度上定义的常见准周期结构不同,我们系统中的准周期性是在数纳米的莫尔长度尺度上定义的。这种新颖的“莫尔准周期晶体”使我们能够调节化学势,从而使电子系统在低能下的类周期性区域与更高能量下的强准周期区域之间进行调控,后者容纳了大量弱色散态。有趣的是,在准周期区域中,我们在味对称性破缺相变附近观察到超导性,后者表明电子相互作用在该区域中发挥着重要作用。在未来具有原位可调谐性的系统中,相互作用现象的普遍存在不仅对研究准周期系统有用,而且可能为相关周期性莫尔晶体中的电子有序提供见解。我们预计,通过改变层数和扭转角以及使用不同的二维组件来扩展这一新平台以工程化准周期晶体,将催生一个新的量子材料家族,用于研究强相互作用准周期晶体的性质。

英文摘要:

Electronic states in quasiperiodic crystals generally preclude a Bloch description, rendering them simultaneously fascinating and enigmatic. Owing to their complexity and relative scarcity, quasiperiodic crystals are underexplored relative to periodic and amorphous structures. Here, we introduce a new type of highly tunable quasiperiodic crystal easily assembled from periodic components. By twisting three layers of graphene with two different twist angles, we form two moiré patterns with incommensurate moiré unit cells. In contrast to many common quasiperiodic structures that are defined on the atomic scale, the quasiperiodicity in our system is defined on moiré length scales of several nanometers. This novel "moiré quasiperiodic crystal" allows us to tune the chemical potential and thus the electronic system between a periodic-like regime at low energies and a strongly quasiperiodic regime at higher energies, the latter hosting a large density of weakly dispersing states. Interestingly, in the quasiperiodic regime we observe superconductivity near a flavor-symmetry-breaking phase transition, the latter indicative of the important role electronic interactions play in that regime. The prevalence of interacting phenomena in future systems with in situ tunability is not only useful for the study of quasiperiodic systems, but it may also provide insights into electronic ordering in related periodic moiré crystals. We anticipate that extending this new platform to engineer quasiperiodic crystals by varying the number of layers and twist angles, and by using different two-dimensional components, will lead to a new family of quantum materials to investigate the properties of strongly interacting quasiperiodic crystals.

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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