Hole pairs in a spin liquid: Influence of electrostatic hole-hole repulsion

摘要

The stability of hole bound states in the t-J model including short-range Coulomb interactions is analyzed using computational techniques on ladders with up to 2x30 sites. Far a nearest-neighbor (NN) hole-hole repulsion, the two-holes bound state is surprisingly robust and breaks only when the repulsion:is several times the exchange J. At similar to 10% hole doping the pairs break only for a NN repulsion as large as V similar to 4J. Pair-pail correlations remain robust in the regime of hole binding. The results support electronic hole-pairing mechanisms on ladders based on holes moving in spin-liquid backgrounds. Implications in two dimensions are also presented. The need for better estimations of the range and strength of the Coulomb interaction in copper oxides is remarked. [S0163-1829(99)50902-8]. [References: 22]