Lehrstuhl für Theoretische Festkörperphysik, Staudstr. 7-B2, 91058, Erlangen, Germany.
Max-Planck-Institut für Mikrostrukturphysik Weinberg 2, D-06120, Halle, Germany.
Nat Commun. 2017 Aug 24;8(1):342. doi: 10.1038/s41467-017-00397-8.
Charge transport at the Dirac point in bilayer graphene exhibits two dramatically different transport states, insulating and metallic, that occur in apparently otherwise indistinguishable experimental samples. We demonstrate that the existence of these two transport states has its origin in an interplay between evanescent modes, that dominate charge transport near the Dirac point, and disordered configurations of extended defects in the form of partial dislocations. In a large ensemble of bilayer systems with randomly positioned partial dislocations, the distribution of conductivities is found to be strongly peaked at both the insulating and metallic limits. We argue that this distribution form, that occurs only at the Dirac point, lies at the heart of the observation of both metallic and insulating states in bilayer graphene.In seemingly indistinguishable bilayer graphene samples, two distinct transport regimes, insulating and metallic, have been identified experimentally. Here, the authors demonstrate that these two states originate from the interplay between extended defects and evanescent modes at the Dirac point.
双层石墨烯中的狄拉克点的电荷输运表现出两种截然不同的输运状态，即绝缘态和金属态，而这两种状态出现在明显无法区分的实验样品中。我们证明，这两种输运状态的存在源于在狄拉克点附近主导电荷输运的消逝模式与以部分位错形式存在的扩展缺陷的无序配置之间的相互作用。在具有随机位置部分位错的大双层系统集合中，发现电导率的分布在绝缘和金属极限处都强烈地出现峰值。我们认为，这种仅在狄拉克点处发生的分布形式是在双层石墨烯中观察到金属态和绝缘态的核心。
