论文标题
微型扭曲的双层石墨烯中的山谷电流分离器
Valley-Current Splitter in Minimally Twisted Bilayer Graphene
论文作者
论文摘要
我们研究了三个拓扑零线的交点上的电子传输性能，作为在微型扭曲的双层石墨烯中产生的基本电流分区节点。与两个相交零线的分区定律不同，我们发现（i）传入电流可以分配到左右相邻拓扑通道中，并且（ii）前向传播电流非零。通过将Fermi能量从电荷中的阴极调整到带边缘，分隔到三个传出通道中的电流几乎相等。此外，我们发现当前的分区节点可以设计为由电门控制的完美山谷过滤器和能量分离器。通过更改相对电场幅度，三个拓扑零线的交点可以平稳地转换为单个零线，并且可以精确控制当前分区。我们通过更改费米能量，能量间隙的大小和中央无间隙区域的大小来系统地调节该设备的可用方法。当前的分区也受磁场和系统大小的影响。我们的结果提供了微观传输特性的微观描述，该特性在微型双层石墨烯的单元牢房周围，对电子束拆分器和干涉仪设备的设计具有深远的影响。
We study the electronic transport properties at the intersection of three topological zero-lines as the elementary current partition node that arises in minimally twisted bilayer graphene. Unlike the partition laws of two intersecting zero-lines, we find that (i) the incoming current can be partitioned into both left-right adjacent topological channels and that (ii) the forward-propagating current is nonzero. By tuning the Fermi energy from the charge-neutrality point to a band edge, the currents partitioned into the three outgoing channels become nearly equal. Moreover, we find that current partition node can be designed as a perfect valley filter and energy splitter controlled by electric gating. By changing the relative electric field magnitude, the intersection of three topological zero-lines can transform smoothly into a single zero line, and the current partition can be controlled precisely. We explore the available methods for modulating this device systematically by changing the Fermi energy, the energy gap size, and the size of central gapless region. The current partition is also influenced by magnetic fields and the system size. Our results provide a microscopic depiction of the electronic transport properties around a unit cell of minimally twisted bilayer graphene and have far-reaching implications in the design of electron-beam splitters and interferometer devices.
