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arXiv · 1707.04212

Collective charge excitations and the metal-insulator transition in the square lattice Hubbard-Coulomb model

Maksim Ulybyshev·Christopher Winterowd·Savvas Zafeiropoulos
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Abstract

In this article, we discuss the non-trivial collective charge excitations (plasmons) of the extended square-lattice Hubbard model. Using a fully non-perturbative approach, we employ the hybrid Monte Carlo algorithm to simulate the system at half-filling. A modified Backus-Gilbert method is introduced to obtain the spectral functions via numerical analytic continuation. We directly compute the single-particle density of states which demonstrates the formation of Hubbard bands in the strongly-correlated phase. The momentum-resolved charge susceptibility is also computed on the basis of the Euclidean charge density-density correlator. In agreement with previous EDMFT studies, we find that at large strength of the electron-electron interaction, the plasmon dispersion develops two branches.

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Maksim Ulybyshev, Christopher Winterowd, Savvas Zafeiropoulos. 2017-11-10. Collective charge excitations and the metal-insulator transition in the square lattice Hubbard-Coulomb model. https://doi.org/10.1103/physrevb.96.205115

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