Valley-polarized pumping current in zigzag graphene nanoribbons with different spatial symmetries Project supported by the National Natural Science Foundation of China (Grant Nos. 11704190, 11874221, and 11504240) and the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20171030). |
(color online) Valley-polarized pumping current of asymmetric ZGNRs as a function of the Fermi level with a static potential V0 = 0.2 V and a pumping potential Vp = 50 mV applied on different pumping regions. The initial phase is set to be ϕ1 = 0 and ϕk = 2,3,4 = π/2. |