An extended Hubbard model containing besides the kinetic energy, on-site, nearest-neighbor and bond-charge interactions also next-nearest-neighbor interaction terms was analysed on the line of Strack and Vollhardt  in order to obtain approximation-free information about its phase diagram in T = 0 and D > 1 dimensional case. The obtained phase diagram regions are given by sufficient conditions written for the model parameters, presenting strong next-nearest-neighbor dependence and revealing an interesting physics. For the obtained phase diagram regions the exact ground state energy and ground state wave functions were deduced, describeing a phase separation, different type of charge-density waves and a paramagnetic phase within the studied case.
ASJC Scopus subject areas
- Physics and Astronomy(all)