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Persistent URL http://purl.org/net/epubs/work/51177
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Record Id 51177
Title Effect of covalent bonding on magnetism and the missing neutron intensity in copper oxide compounds
Abstract Theories involving highly energetic spin fluctuations are among the leading contenders for explaining high-temperature superconductivity in the cuprates1. These theories could be tested by inelastic neutron scattering (INS), as a change in the magnetic scattering intensity that marks the entry into the superconducting state provides a precise quantitative measure of the spin-interaction energy involved in the superconductivity.However, the absolute intensities of spin fluctuations measured in neutron scattering experiments vary widely, and are usually much smaller than expected from fundamental sum rules, resulting in "missing" INS intensity. Here, we solve this problem by studying magnetic excitations in the one-dimensional related compound, Sr2CuO3, for which an exact theory of the dynamical spin response has recently been developed. In this case, the missing INS intensity can be unambiguously identified and associated with the strongly covalent nature of magnetic orbitals.We find that whereas the energies of spin excitations in Sr2CuO3 arewell described by the nearestneighbour spin-1/2 Heisenberg Hamiltonian, the corresponding magnetic INS intensities are modified markedly by the strong 2p-3d hybridization of Cu and O states. Hence, the ionic picture of magnetism, where spins reside on the atomic-like 3d orbitals of Cu2C ions, fails markedly in the cuprates.
Organisation ISIS , ISIS-MAPS , STFC
Keywords Physics
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Language English (EN)
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Journal Article Nat Phys 5, no. 12 (2009): 867-872. doi:10.1038/nphys1405 2009