Transport properties of one-dimensional extended Hubbard model with repulsive and attractive Coulomb interaction

一次元拡張ハバード模型の輸送特性

大西 弘明  ; Dagotto, E.*

Onishi, Hiroaki; Dagotto, E.*

We study the transport properties of a one-dimensional extended Hubbard model with the intra-site and the inter-site Coulomb interactions at half filling, analyzing the time evolution of wavepackets by a time-dependent DMRG method. When is repulsive and =0, the charge wavepacket cannot transmit into the Mott insulator due to a charge gap, while a part of the spin wavepacket enters the Mott insulator, since there is no spin gap. Thus we observe the spin injection in the metal/Mott-insulator junction. On the other hand, the charge/spin wavepackets in the attractive case show exactly the same behavior of the spin/charge wavepackets in the repulsive case due to the conversion of spin and charge degrees of freedom via the particle-hole transformation. When we introduce attractive in addition to attractive , we clearly observe that the charge wavepacket exhibits a negative reflection, indicating the Andreev reflection in the metal/superconductor junction.