Close inspection of plasmon excitations in cuprate superconductors

Abstract

Recently resonant inelastic x-ray scattering experiments reported fine details of the charge excitations around the in-plane momentum ${\mathbf{q}}_{\ensuremath{\parallel}}=(0,0)$ for various doping rates in electron-doped cuprates ${\text{La}}_{2\ensuremath{-}x}{\text{Ce}}_{x}{\text{CuO}}_{4}$. We find that those new experimental data are well captured by acousticlike plasmon excitations in a microscopic study of the layered $t\ensuremath{-}J$ model with the long-range Coulomb interaction. The acousticlike plasmon is not a usual plasmon typical to the two-dimensional system, but has a small gap proportional to the interlayer hopping ${t}_{z}$.

Topics & Concepts