Electron-Hole Asymmetry of Quantum Collective Excitations in High-Tc Copper Oxides

M. Fidrysiak Institute of Theoretical Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland

Full Text PDF

We carry out a systematic study of collective spin and charge excitations for the canonical single-band Hubbard, t-J-U, and t-J models of high-temperature copper-oxide superconductors, both on electron- and hole-doped side of the phase diagram. A recently developed variational wave function approach, combined with the expansion in the inverse number of fermionic flavors, is employed. All three models exhibit a substantial electron-hole asymmetry of magnetic excitations, with a robust paramagnon emerging for hole-doping, in agreement with available resonant inelastic X-ray scattering data for the cuprates. The t-J model yields additional high-energy peak in the magnetic spectrum that is not unambiguously identified in spectroscopy. For all considered Hamiltonians, the dynamical charge susceptibility contains a coherent mode for both hole- and electron doping, with overall bandwidth renormalization controlled by the on-site Coulomb repulsion. Away from the strong-coupling limit, the antiferromagnetic ordering tendency is more pronounced on the electron-doped side of the phase diagram.

DOI:10.12693/APhysPolA.143.180 topics: strongly-correlated electrons, paramagnons, charge fluctuations, cuprates