Spin-charge interaction and physical electron spectral function in t-J model

Starting with the one-band t-J model and using the slave-boson method to enforce the constraint of no double occupation, we examine the role of the spin-charge interaction in the π-flux phase at half-filling and the uniform resonantvalence- bond mean-field solution away from half-filling. In particular, we calculate the phyiscal electron spectral function. By using the functional integral approach, we developed a self-consistent scheme for the physical electron spectral function. A bandwidth of 8t in the incoherent part of the electron spectral function is obtained both at half-filling and away from half-filling. At half-filling, we found a double-peak structure in the incoherent background of the electron spectral function and this structure persists to small doping regime. The spin-charge interaction also renormalises the holon quasiparticle bandwidth to scale with J. Upon small doping, the electron spectral function contains two dominant distinct features, namely a low-energy quasiparticle peak with bandwidth of order J, and broad valence peaks at energies of order t. The structure in the incoherent background is interpreted due to the strong spin-charge interaction near the points (0,0) and ([pi, pi]) of the first Brillouin zone. The instability of bose-condensation of holon is also examined. We found that the spin-charge interaction is not strong enough to destroy the bose-condenation and a large fraction of holon still condense at zero temperature