Topological charge pump by surface acoustic waves
Zheng Yi, Feng Shi-Ping, Yang Shi-Jie
       

Phase diagram of current plateaus versus V0 and VSAW. Each region corresponds to the summation of Chern numbers of the filled bands. Inset: schematic plot of staircase-like pumping current versus the Fermi energy for VSAW = V0 = 100ER.