Jaskólski W, Pelc M, Bryant Garnett W, Chico Leonor, Ayuela A
Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Toruń, Poland.
Donostia International Physics Center (DIPC), Paseo Manuel Lardizabal 4, 20018 Donostia-San Sebastián, Spain.
2d Mater. 2018;5(2). doi: 10.1088/2053-1583/aaa490.
Experiments in gated bilayer graphene with stacking domain walls present topological gapless states protected by no-valley mixing. Here we research these states under gate voltages using atomistic models, which allow us to elucidate their origin. We find that the gate potential controls the layer localization of the two states, which switches non-trivially between layers depending on the applied gate voltage magnitude. We also show how these bilayer gapless states arise from bands of single-layer graphene by analyzing the formation of carbon bonds between layers. Based on this analysis we provide a model Hamiltonian with analytical solutions, which explains the layer localization as a function of the ratio between the applied potential and interlayer hopping. Our results open a route for the manipulation of gapless states in electronic devices, analogous to the proposed writing and reading memories in topological insulators.
在具有堆叠畴壁的门控双层石墨烯中进行的实验呈现出由无谷混合保护的拓扑无隙态。在此，我们使用原子模型研究这些态在栅极电压下的情况，这使我们能够阐明它们的起源。我们发现栅极电势控制着这两种态的层定位，其会根据所施加的栅极电压大小在层间以非平凡的方式切换。我们还通过分析层间碳键的形成展示了这些双层无隙态是如何从单层石墨烯的能带中产生的。基于此分析，我们提供了一个具有解析解的模型哈密顿量，它将层定位解释为所施加电势与层间跳跃之比的函数。我们的结果为电子器件中无隙态的操控开辟了一条途径，类似于在拓扑绝缘体中所提出的写入和读取存储器的方式。
