论文标题
在强磁场中的人工石墨烯：大量电流分布和量子相变
Artificial Graphene in a Strong Magnetic Field: Bulk Current Distribution and Quantum Phase Transitions
论文作者
论文摘要
我们介绍了2DEG的平衡电流密度和Chern数量的计算，该势具有无限条纹几何形状和垂直磁场的周期电势。我们考虑具有较大（A = 120 nm）晶格间距的抗点的三角形晶格。这样的系统被称为人工石墨烯（AG）。为了计算当前的密度，我们在一组Landau级别的基础状态下数值对角度化AG Hamiltonian，这考虑了不同Landau级别之间的耦合。我们的计算表明，在量子大厅测量的典型磁场上，大部分样品中存在扩展的电流流。我们以潜在的强度研究了这些流的缩放。对AG能量水平的了解使我们能够计算与每个能量差距相关的Chern数字。我们证明，在调整电势调制的高度时，Chern数可以在两个不同值之间进行过渡。
We present calculations of the equilibrium current density and Chern numbers for a 2DEG in a periodic potential with infinite strip geometry and a perpendicular magnetic field. We consider a triangular lattice of anti-dots with large (a = 120 nm) lattice spacing. Such a system is known as artificial graphene (AG). To compute the current density we numerically diagonalise the AG Hamiltonian over a set of Landau level basis states, this takes into account coupling between different Landau levels. Our calculations show that, at magnetic fields typical for quantum Hall measurements, extended streams of current are present in the bulk of the sample. We investigate the scaling of these streams with potential strength. Knowledge of the AG energy levels allows us to compute the Chern number associated with each energy gap. We demonstrate that in tuning the height of the potential modulation the Chern number can undergo a transition between two different values.
