Physical mechanisms in electron doped high T-c systems

Electronic states of electron doped high T-c material Nd2-xCexCuO4 have bee n investigated in detail based on the results of detailed band calculation performed in previous publications. It is proposed that a complicated multi -impurity state with one hole and two electrons is realized in the similar sense as in SmS and EuB6 studied before by us. This situation is most clear ly seen in the photoemission measurement, and various anomalies due to two carriers are well explained selfconsistently. In particular, the supercondu cting character is essentially the same as the overdoped region of La2-xSrx CuO4, where the pair wave function for the paired magnetic polaron is thoug ht to be predominantly s-character.