Doping dependence of charge dynamics in electron-doped cuprates

Within the t-t′-J model, the doping dependence of charge dynamics in the electron-doped cuprates is studied. The conductivity spectrum shows an unusual pseudogap structure with a low-energy peak appearing at ω∼0 and an rather sharp midinfrared peak appearing around ω∼0.3|t|, and the resistivity exhibits a crossover from the high temperature metallic-like to low temperature insulating-like behavior in the relatively low doped regime, and a metallic-like behavior in the relatively high doped regime, in qualitative agreement with experiments. Our results also show that the unusual pseudogap structure is intriguingly related to the strong antiferromagnetic correlation in the system.