Strongly Correlated Systems with Long-Ranged Coulomb Interaction

Motivated by recent experimental studies [1] of the q dependent charge density fluctuations in certain 2-dimensional cuprate materials, we extend the extremely correlated Fermi liquid theory (ECFL) to include long-ranged Coulomb interactions V_c. The t-J-V_c model studied here thus includes the effect of short-ranged Hubbard-Gutzwiller correlations and the long-ranged Coulomb interactions. Following Nozières' important work on the dielectric function, we develop an expression for the q dependent susceptibility with a novel self-energy ψ(q), satisfying the requirements arising from both low and high ω limits. Combining the above with the ECFL Green's function, we present results for the dynamical charge susceptibility, the dielectric function, the current susceptibility, the optical conductivity, and the plasma frequency over the Brillouin zone. Our study provides insight into the smearing of sharp features expected from weak coupling models and also a calculation for the first moment of the structure function and some other variables that may be available in the future.

[1] Husain et al. Phys. Rev. X 9, 041062 (2019)