Electronic states in the antiferromagnetic phase of electron-doped high-Tccuprates

We investigate the electronic states in the antiferromagnetic (AF) phase of electron-doped cuprates by using numerically exact diagonalization technique for a $t-t^{\prime }-t^{″}-J$ model. When AF correlation develops with decreasing temperature, a gaplike behavior emerges in the optical conductivity. Simultaneously, the coherent motion of carriers due to the same sublattice hoppings is enhanced. We propose that the phase is characterized as an AF state with small Fermi surface around the momentum $\mathbf{k}=(\pi ,0)$ and $(0,\pi ).\mathrm{}$ This is a remarkable contrast to the behavior of hole-doped cuprates.