石墨烯莫尔异质结中局域-巡游电子的竞争和耦合  

Competition and coupling effect between localized and iterant electrons in graphene moiréheterostructures

作　　者：陈墨雨 谢永勤 程斌 梁世军 缪峰[1] CHEN Moyu;XIE Yongqin;CHENG Bin;LIANG Shijun;MIAO Feng(Institute of Brain-Inspired Intelligence,Nanjing University,Nanjing 210093,China;School of Physics,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京大学类脑智能科技研究中心,南京210093 [2]南京理工大学物理学院,南京210094

出　　处：《中国科学：物理学、力学、天文学》2024年第12期1-12,共12页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:12322407,62122036,62034004,61921005,12074176)资助项目。

摘　　要：由二维量子材料构筑的范德华异质结展现出丰富的界面衍生量子态,并具有出色的物态可调性,不但为探索新奇量子物态和物态演化规律提供强大的可调平台,也为开发新原理电子器件功能提供丰富的材料库.本文将结合我们过去几年在石墨烯莫尔异质结体系中的电子输运工作,详细讨论其中的巡游电子与局域电子之间的竞争与耦合作用对新物态的形成与演化的影响,以及对新原理器件设计所提供的新思路.首先通过对巡游-局域电子耦合强度的原位调控,我们实现了对电子晶体的量子融化过程的高精度观测,首次观测到量子两步临界性和量子赝临界性等新奇量子临界行为,展示了石墨烯莫尔异质结在可调量子临界行为固态量子模拟上的巨大潜力.其次,分层的巡游电子和局域电子之间的耦合作用可以诱导出非常规电子型铁电,其铁电的极化强度具有准连续性,有望满足高精度神经形态计算中对可精准调控多态的需求.特别地,电子型铁电可以使得铁电与其他量子物态例如陈绝缘态共存,这为设计开发噪声免疫神经形态计算等全新物理计算硬件提供了独特的平台.Van der Waals heterostructures constructed from two-dimensional quantum materials exhibit rich emergent interfacial quantum states and excellent tunability of those physical properties.These materials not only provide a robust platform for exploring novel quantum states and their evolution but also offer a diverse material library for developing new principles in electronic device functionalities.This article introduces the electric transport studies in graphene-based moiréheterostructures performed by us in the past few years,extensively discussing the competition and coupling effects between itinerant and localized electrons.These effects influence the formation and evolution of new quantum states and offer new perspectives for designing advanced electronic devices.We achieved high-precision observations of the quantum melting process in electron crystals by in-situ tuning the coupling strength between itinerant and localized electrons.We observed novel quantum critical behaviors,including quantum two-stage criticality and quantum pseudo criticality,for the first time.These findings underscore the substantial potential of graphene moiréheterostructures in solid-state quantum simulations,especially for investigating the evolution of quantum critical behaviors.Furthermore,the coupling between layer-resolved itinerant and localized electrons can induce unconventional electronic-type ferroelectricity.The polarization intensity of this ferroelectricity exhibits quasi-continuous and precise control over multiple states that are crucial for high-precision neuromorphic computing.Notably,electronic-type ferroelectricity allows the coexistence of ferroelectricity and other quantum states such as Chern insulators,offering a unique platform for designing noise-immune neuromorphic computing and other new physical computing hardware.

关 键 词：二维材料 电子输运 物态调控 物理计算 

分 类 号：O469[理学—凝聚态物理] TB34[理学—电子物理学]