2004/09/29 by A. Foussats, Adriana Foussats, A. Greco +1
Physics and Astronomy · #Charge (physics) #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Coulomb #Fermi liquid theory #Hubbard model #Mathematical physics #Phase (matter) #Phase diagram #Physics #Physics of Superconductivity and Magnetism #Propagator #Quantum and electron transport phenomena #Quantum mechanics #Superconductivity #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.70.205123
10 pages, 8 figures, to appear in Phys. Rev. B
arxiv created 2004/09/29 · openalex publication_date 2004/11/18 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We have introduced a new perturbative approach for t\text\ensuremath-J\text\ensuremath-V model where Hubbard operators are treated as fundamental objects. Using our vertices and propagators we have developed a controllable large-N expansion to calculate different correlation functions. We have investigated charge density-density response and the phase diagram of the model. The charge correlations functions are not very sensitive to the value of J and they show collective peaks (or zero sound) which are more pronounced when they are well separated (in energy) from the particle-hole continuum. For a given J a Fermi liquid state is found to be stable for doping \ensuremathδ larger than a critical doping \ensuremathδc. \ensuremathδc decreases with decreasing J. For the physical region of the parameters and, for \ensuremathδ<\ensuremathδc, the system enters in an incommensurate flux or DDW phase. The inclusion of the nearest-neighbor Coulomb repulsion V leads to a charge density wave phase when V is larger than a critical value Vc. The dependence of Vc with \ensuremathδ and J is shown. We have compared the results with other ones in the literature.