Low-energy effective action of lightly doped two-leg t-J ladders

Article

关键词: SPIN LADDERS;    QUANTUM ANTIFERROMAGNET;    2-LEG LADDERS;    SUPERCONDUCTIVITY;    CONFINEMENT;    CHAINS;    GAP;   

DOI  :  10.1103/PhysRevB.59.1290

来源: SCIE

【 摘 要 】

We propose a low-energy effective theory of lightly doped two-leg t-J ladders with the help of slave fermion technique. The continuum limit of this model consists of two kinds of Dirac fermions, which are coupled to the O(3) nonlinear sigma model in terms of the gauge coupling with opposite sign of charges. In addition to the gauge interaction, there is another kind of attractive force between these Dirac fermions, which arises from the short-ranged antiferromagnetic order. We show that the latter is essential to determine the low energy properties of lightly doped two-leg t-J ladders. The effective Hamiltonian we obtain is a bosonic Gaussian model and the boson field basically describes the particle-density fluctuation. We also find two types of gapped spin excitations. Finally, we discuss the possible instabilities: charge density wave and singlet superconductivity (SC). We find that the SC instability dominates in our approximation. Our results indicate that lightly doped ladders fall into the universality class of Luther-Emery model. [S0163-1829(99)08801-3].

【 授权许可】

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