Spin-phonon coupling, q-dependence of spin excitations and high-T${}_C$ superconductivity from band models

Abstract

An understanding of spin excitations in cuprates is essential since the mechanism of high-T${}_C$ superconductivity might be linked to spin fluctuations. Band calculations for long "1-dimensional" unit cells of La${}_2$CuO${}_4$ show that the coupling between antiferromagnetic spin waves and phonons is larger for distortions of oxygens than for Cu or La. When this result is applied to a 2-dimensional, free-electron like band, it leads to a q-dependent spin excitation spectrum in good agreement with recent experiments. It is argued that important parameters for spin-phonon coupling, which comes out from the comparison between experiment and theory, are relevant for the mechanism of superconductivity, and are large enough to explain a high T${}_C$.

(1 figure, 1 Table, 4 pages)

References in corpus (6)

• Spin dynamics in the pseudogap state of a high-temperature superconductor
• Two energy scales in the spin excitations of the high-T_c superconductor La${}_{2-x}$Sr${}_x$CuO${}_4$
• Momentum dependence of the electron-phonon coupling and self-energy effects in YBa_2Cu_3O_7 within the local density approximation
• Magnetic Excitations of the Diagonal Incommensurate Phase in Lightly-Doped La2-xSrxCuO4
• Properties of high-T${}_C$ copper oxides from the nearly-free electron model
• Absence of an isotope effect in the magnetic resonance in high-$T_c$ superconductors