Spin-gap phases in Tomonaga-Luttinger liquids

Article

关键词: T-J MODEL;    RENORMALIZATION-GROUP-ANALYSIS;    NEAREST NEIGHBOR INTERACTIONS;    DIMENSIONAL HUBBARD-MODEL;    CONFORMAL-INVARIANCE;    HEISENBERG CHAIN;    CRITICAL-POINT;    T-J-J' MODEL;    FERMI GAS;    XY-MODEL;   

DOI  :  10.1103/PhysRevB.60.7850

来源: SCIE

【 摘 要 】

We give details of the analysis of critical properties of spin-gap phases in one-dimensional lattice electron models. In Tomonaga-Luttinger (TL) liquid theory, the spin-gap instability occurs when the backward scattering changes from repulsive to attractive. This transition point is, shown to be equivalent to that of the level-crossing of the singlet and triplet excitation spectra, using the c=1 conformal field theory and the renormalization group. Based on this notion, the transition point between the TL liquid and the spin-gap phases can be determined with high-accuracy, from the numerical data of finite-size clusters. We also discuss the boundary conditions and discrete symmetries to extract these excitation spectra. This technique is applied to the extended Hubbard model, the t-J model, and the t-J-J' model, and their phase diagrams are obtained. We also discuss the relation between our results and analytical solutions in weak-coupling and low-density limits.

【 授权许可】

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