Exact ground and excited states of a t-J ladder doped with two holes
Indrani Bose; Saurabh Gayen
Журнал:
Journal of Physics: Condensed Matter
Дата:
1999-08-23
Аннотация:
A two-chain ladder model is considered that is described by the strong-coupling t-t´-J-J´ Hamiltonian. For the case of two holes moving in a background of antiferromagnetically interacting spins, exact, analytical results are derived for the ground-state energy and low-lying excitation spectrum. The ground state is a bound state of two holes with total spin S = 0. The charge excitation is gapless and the spin excitation has a gap. The corresponding wave functions are also exactly determined. The bound hole pair is found to have symmetry of the d-wave type. In the limit of strong rung coupling, the model maps onto an effective hard-core-boson model which exhibits dominant superconducting pairing correlations.
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