Canted Antiferromagnetic Phase of the v=0 Quantum Hall State in Bilayer Graphene
Canted Antiferromagnetic Phase of the v=0 Quantum Hall State in Bilayer Graphene
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DOI：
10.1103/physrevlett.109.046803
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发表时间：
2012-07-27
影响因子：
8.6
通讯作者：
Kharitonov, Maxim
中科院分区：
文献类型：
--
作者：
Kharitonov, Maxim
为了理解双层石墨烯中强绝缘的v=0量子霍尔态的本质，我们在量子霍尔铁磁性的框架下发展了这种态的理论。在存在同位旋各向异性、垂直电场和塞曼效应的情况下，得到的一般相图由自旋极化的铁磁(F)、倾斜的反铁磁(CAF)以及部分(PLP)和完全(FLP)层极化的相组成。我们讨论了这些位相的边缘输运性质。将我们的发现与悬置双栅器件的最新数据相比较，我们得出结论：在较低电场下在双层石墨烯中实现的绝缘态v=0为CaF相。我们还预测了当磁场分别从绝缘CaF相和FLP相倾斜到金属边缘电导为2e(2)/h的F相时，绝缘体-金属相变将是连续的和急剧的，这可能在可用场的范围内，并允许人们从实验上识别和区分相。
Motivated to understand the nature of the strongly insulating v = 0 quantum Hall state in bilayer graphene, we develop the theory of the state in the framework of quantum Hall ferromagnetism. The generic phase diagram, obtained in the presence of the isospin anisotropy, perpendicular electric field, and Zeeman effect, consists of the spin-polarized ferromagnetic (F), canted antiferromagnetic (CAF), and partially (PLP) and fully (FLP) layer-polarized phases. We address the edge transport properties of the phases. Comparing our findings with the recent data on suspended dual-gated devices, we conclude that the insulating v = 0 state realized in bilayer graphene at lower electric field is the CAF phase. We also predict a continuous and a sharp insulator-metal phase transition upon tilting the magnetic field from the insulating CAF and FLP phases, respectively, to the F phase with metallic edge conductance 2e(2) / h, which could be within the reach of available fields and could allow one to identify and distinguish the phases experimentally.