Out-of-phase Plasmon Excitations in the Trilayer Cuprate Bi$_2$Sr$_2$Ca$_2$Cu$_3$O$_{10+δ}$

S. Nakata; M. Bejas; J. Okamoto; K. Yamamoto; D. Shiga; R. Takahashi; H. Y. Huang; H. Kumigashira; H. Wadati; J. Miyawaki; S. Ishida; H. Eisaki; A. Fujimori; A. Greco; H. Yamase; D. J. Huang; H. Suzuki

doi:10.1103/PhysRevB.111.165141

paper

Out-of-phase Plasmon Excitations in the Trilayer Cuprate Bi $_{2}$ Sr $_{2}$ Ca $_{2}$ Cu $_{3}$ O $_{10 + δ}$

arXiv:2502.03779 · doi:10.1103/PhysRevB.111.165141

Abstract

Within a homologous series of cuprate superconductors, variations in the stacking of CuO $_{2}$ layers influence the collective charge dynamics through the long-range Coulomb interactions. We use O $K$ -edge resonant inelastic x-ray scattering to reveal plasmon excitations in the optimally-doped trilayer Bi $_{2}$ Sr $_{2}$ Ca $_{2}$ Cu $_{3}$ O $_{10 + δ}$ . The observed plasmon exhibits nearly $q_{z}$ -independent dispersion and a large excitation gap of approximately 300 meV. This mode is primarily ascribed to the $ω_{-}$ mode, where the charge density on the outer CuO $_{2}$ sheets oscillates out of phase while the density in the inner sheet remains unaltered at $q_{z} = 0$ . The intensity of the acoustic $ω_{3}$ mode is relatively weak and becomes vanishingly small near $(q_{x}, q_{y}) = (0, 0)$ . This result highlights a qualitative change in the eigenmode of the dominant low-energy plasmon with the number of CuO $_{2}$ layers.

Out-of-phase Plasmon Excitations in the Trilayer Cuprate Bi2​Sr2​Ca2​Cu3​O10+δ​

Abstract

Out-of-phase Plasmon Excitations in the Trilayer Cuprate Bi $_{2}$ Sr $_{2}$ Ca $_{2}$ Cu $_{3}$ O $_{10 + δ}$