Possible quantized charge pump in bilayer and trilayer graphene
Possible quantized charge pump in bilayer and trilayer graphene
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DOI：
10.1088/1367-2630/ab69b6
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发表时间：
2020-01
影响因子：
3.3
通讯作者：
Mei-Juan Wang;Jun Wang;Junfeng Liu
中科院分区：
文献类型：
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作者：
Mei-Juan Wang;Jun Wang;Junfeng Liu
我们报告了基于双层和三层石墨烯系统的双参数绝热电荷泵的理论研究。两个相互垂直且具有相位滞后的时间相关电场被视为泵浦电势，这会在每个泵浦区域中产生瞬时能隙。基于连续介质模型和晶格模型，我们表明，当费米能量恰好驻留在打开的能隙中时，双层和三层石墨烯系统的泵浦结果非常不同：双层系统没有泵浦电流，而基于三层石墨烯的泵浦器件中出现了量子化电荷泵浦效应。这种差异可以通过两个系统中狄拉克电子的不同贝里相来解释。我们的发现可能有助于开发量化电荷泵器件。
We report a theoretic study of the two-parameter adiabatic charge pump based on the bilayer and trilayer graphene systems. The two perpendicular time-dependent electric fields with a phase lag between them are taken as the pumping potentials, which induce an instant energy gap in each pumping region. Based on both a continuum model and a lattice model, we show that the pumping results from the bilayer and trilayer graphene systems are very different when the Fermi energy happens to reside in the opened energy gap: there is no pumping current for the bilayer system whereas a quantized charge pumping effect emerges in the trilayer-graphene based pump device. This difference can be accounted for by the different Berry phases of Dirac electrons in the two systems. Our findings may shed a light on developing a quantized charge pumping device.