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可调整的相关的切尔恩绝缘体和铁磁在摩尔超级网中

Guorui Chen^1,2, Aaron L Sharpe^3,4, Eli J Fox^4,5

¹Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.

|March 6, 2020

概括

研究人员在ABC三层石墨烯/hBN摩埃尔超级网中观察到相关的切恩绝缘体. 这种拓状态表现出铁磁性和量子化的霍尔电阻,为新的拓材料铺平了道路.

科学领域:

凝聚物质物理学
材料科学
量子现象

背景情况:

2D电子系统中的量子霍尔效应是一个以有限的切尔恩数和奇拉边缘状态为特征的拓状态.
在没有外部磁场的情况下表现出整数量子霍尔效应的切尔恩绝缘体在理论上被提出为晶格模型.
ABC三层石墨烯/六角化物 (ABC-TLG/hBN) 摩尔超级网格提供了一个可调的平台来探索切尔恩绝缘体,因为它们具有平面的,在拓上非平的小频段.

研究的目的:

在ABC-TLG/hBN摩埃尔超网中实验观察和描述相关的切尔恩绝缘体.
通过电场来研究Moiré小频段中切尔恩数的可调性.
探索观察到的拓状态的磁性和传输特性.

主要方法:

制造ABC-TLG/hBN摩尔特超级网格
在不同磁场和电场下的电传输测量.
霍尔电阻量化和磁性歇斯底里分析.

主要成果:

在ABC-TLG/hBN系统中观察相关的切尔恩绝缘体.
通过反转应用的垂直电场来证明电调的切尔恩数.
在四分之一填充和磁场>0.4 T时,对拓孔小带的量化哈尔电阻为h/2e^2 (暗示C=2).
对铁磁,磁歇斯底里和零场异常霍尔信号的观察.

结论:

在零磁场的ABC-TLG/hBN摩尔特超级电网中实验实现C=2切恩绝缘体.
这一发现突显了moiré系统在探索物质新型拓状态方面的潜力.
开辟了在平面,拓上非平凡的带中发现相关的拓状态的途径.

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