Plasmon dispersion and the role of the exact constraints on exchange-correlation kernels within time-dependent density functional theory*

Small-wavevector excitations in Coulomb-interacting systems can be decomposed into the high-energy collective longitudinal plasmon and the low-energy single-electron excitations. The random phase approximation (RPA) is exact in the high-density limit but can capture the plasmonic dispersion reasonably even for densities with r_s > 1. The work by Tatarczyk et al. [1] found that the impact of the exchange-correlation kernels is significant and modifies the plasmon dispersion curve. There is however a large difference in the construction and performance of the kernels investigated earlier. Our current work for the jellium model introduces recent model exchange-only and exchange-correlation kernels and discusses the relevance of some exact constraints [2,3] in the construction of the kernel. This work could give a further hint toward a better plasmon dispersion in realistic metals where anomalous behavior was observed with RPA.

[1] K. Tatarczyk, A. Schindlmayr, and M. Scheffler, Phys. Rev. B 63 235106 (2001) [2] J.E. Bates, S. Laricchia and A. Ruzsinszky, Phys. Rev. B 93, 045119 (2016) [3] L.A. Constantin, and J.M. Pitarke, Phys. Rev. B 75, 245127 (2007)