电子非常规跃迁对一维关联体系基态的影响

Effect of Unconventional Electron Hopping on Ground State of the One-Dimensional Correlated System

在弱耦合区域和半满情况下,通过场论方法研究了一维关联电子系统的基态相图.模型哈密顿量包含非常规跃迁、在位作用U和最近邻库仑作用V.研究表明非常规跃迁诱导产生的三体吸引作用影响着体系的量子特性.基态中除了熟悉的电荷密度波相和自旋密度波相,相图中-82tζ/π+2V <U <82tζ/π+2V区域还存在一个键序自旋密度波相.当最近邻库仑作用消失时,在■处体系中发生直接的绝缘-超导相变,在ζ> ζc区域,存在三相超导序的拉亭格液体相.

At weak coupling and at half filling, we investigate the ground-state phase diagram of one-dimensional correlated systems by the field-theory approach. The model Hamiltonian contains a unconventional hopping, an on-site(U) and a nearest-neighbor(V) repulsions. The result shows that the three-body attraction induced by the modulated hopping affects quantum properties of the system. Besides the familiar site-located CDW and SDW states, a bond-located BSDW state is realized in the -8tζ~2/π + 2V < U < 8tζ~2/π + 2V regime of the phase diagram. When the V interaction disappears in the system, a direct insulator-superconductor transition occurs at ■. The Luttinger liquid phase with the TS correlations survives for ζ > ζc.