Commensurate-incommensurate transition in graphene on hexagonal boron nitride
Commensurate-incommensurate transition in graphene on hexagonal boron nitride
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DOI：
10.1038/nphys2954
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发表时间：
2014-06-01
期刊：
影响因子：
19.6
通讯作者：
Novoselov, K. S.
中科院分区：
文献类型：
--
作者：
Woods, C. R.;Britnell, L.;Novoselov, K. S.
当晶体受到周期性电势时，在某些情况下，它可以根据电势的周期性进行自我调整，从而产生一种相称的状态。特别令人感兴趣的是两个公度相之间的拓扑缺陷，如孤子和磁区壁。在这里，我们报道了石墨烯在六方氮化硼(HBN)上的公度-非公度转变。根据两个晶体晶格之间的旋转角，石墨烯既可以拉伸以适应略有不同的hBN周期(对于小角度，导致公度状态)，也可以表现出很小的调整(非公度状态)。在相称状态下，具有匹配晶格常数的区域被累积产生应变的磁区隔开。这种类孤子物体不仅具有重要的基本意义，而且它们的存在也可以解释最近的实验，这些实验观察到石墨烯-hBN异质结构的电子和光学性质发生了很大的变化。
When a crystal is subjected to a periodic potential, under certain circumstances it can adjust itself to follow the periodicity of the potential, resulting in a commensurate state. Of particular interest are topological defects between the two commensurate phases, such as solitons and domain walls. Here we report a commensurate-incommensurate transition for graphene on top of hexagonal boron nitride (hBN). Depending on the rotation angle between the lattices of the two crystals, graphene can either stretch to adapt to a slightly different hBN periodicity (for small angles, resulting in a commensurate state) or exhibit little adjustment (the incommensurate state). In the commensurate state, areas with matching lattice constants are separated by domain walls that accumulate the generated strain. Such soliton-like objects are not only of significant fundamental interest, but their presence could also explain recent experiments where electronic and optical properties of graphene-hBN heterostructures were observed to be considerably altered.