Charge Inversion and Topological Phase Transition at a Twist Angle Induced van Hove Singularity of Bilayer Graphene
Charge Inversion and Topological Phase Transition at a Twist Angle Induced van Hove Singularity of Bilayer Graphene
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DOI：
10.1021/acs.nanolett.6b01906
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发表时间：
2016-08-01
期刊：
影响因子：
10.8
通讯作者：
Smet, Jurgen H.
中科院分区：
文献类型：
--
作者：
Kim, Youngwook;Herlinger, Patrick;Smet, Jurgen H.
态密度中的货车霍韦奇异性（VHS）对晶体的电子和热力学性质起着显著而多样的作用。在临界点，费米面的连通性发生变化，拓扑性质发生转变。然而，在电压旋钮转动时系统地通过VHS并研究其各种影响的机会很少。随着货车德瓦尔斯异质结构的出现，对邻近石墨烯层的原子注册的控制提供了一种前所未有的工具，可以通过传统门控轻松生成低能量VHS。在这里，我们已经解决了磁输运时的化学势交叉的扭曲角诱导VHS在扭曲的双层石墨烯。拓扑相变是实验上公开的突然转换的电子空穴或反之亦然，损失的非零Berry相位和不同的序列的整数量子霍尔态以上和以下的奇异性。
van Hove singularities (VHS's) in the density of states play an outstanding and diverse role for the electronic and thermodynamic properties of crystalline solids. At the critical point the Fermi surface connectivity changes, and topological properties undergo a transition. Opportunities to systematically pass a VHS at the turn of a voltage knob and study its diverse impact are however rare. With the advent of van der Waals heterostructures, control over the atomic registry of neighboring graphene layers offers an unprecedented tool to generate a low energy VHS easily accessible with conventional gating. Here we have addressed magnetotransport when the chemical potential crosses the twist angle induced VHS in twisted bilayer graphene. A topological phase transition is experimentally disclosed in the abrupt conversion of electrons to holes or vice versa, a loss of a nonzero Berry phase and distinct sequences of integer quantum Hall states above and below the singularity.