Spectral weight dichotomy as an intrinsic property of t-t'-t''-J model

Ying Ran, MIT

Abstract: We studied a fully fermionic approach of t-t'-t''-J model in terms of projected wavefunctions, where spinon carries spin and dopon carries both spin and charge. The mixing of spinon and dopon describes superconductivity. We found in a uniform mixing limit, the projected fully fermionic wavefunction(PFFWF) goes back to the usual projected BSC wavefunction. However non-uniform mixing favors the hopping energy, in particular to lower t' and t'' hopping energy, the mixing is suppressed in antinodal point and enhenced around nodal point. The PFFWF captures the dichotomy. We found that on mean-field level, mixing is proportional to Z-. We also found a simple monte-carlo algorithm to calculate Z- on the projected wavefunction. The main result is, to lower t' and t'' hopping energy, Z- natually develops dichotomy-like feature, which means Z- is large in the nodal region and small in the anti-nodal region. This contradicts people's naive guess that to make hopping more coherent, Z- should increase. We emphasize that it is t' and t'' that cause the dichotomy.