Ab initio determination of excitation energies and magnetic couplings in correlated, quasi two-dimensional iridates

Vamshi M. Katukuri; H. Stoll; J. van den Brink; L. Hozoi

doi:10.1103/PhysRevB.85.220402

paper

Ab initio determination of excitation energies and magnetic couplings in correlated, quasi two-dimensional iridates

arXiv:1203.2054 · doi:10.1103/PhysRevB.85.220402

Abstract

To determine the strength of essential electronic and magnetic interactions in the iridates Sr $_{2}$ IrO $_{4}$ and Ba $_{2}$ IrO $_{4}$ - potential platforms for high-temperature superconductivity - we use many-body techniques from wavefunction-based electronic-structure theory. Multiplet physics, spin-orbit interactions, and Ir-O hybridization are all treated on equal footing, fully {\it ab initio}. Our calculations put the lowest d-d excitations of Sr $_{2}$ IrO $_{4}$ /Ba $_{2}$ IrO $_{4}$ at 0.69/0.64 eV, substantially lower than in isostructural cuprates. Charge-transfer excitations start at 3.0/1.9 eV and the magnetic nearest-neighbor exchange coupling is 51/58 meV. Available experimental results are fully consistent with these values, which strongly constrains the parametrization of effective iridate Hamiltonians.

Ab initio determination of excitation energies and magnetic couplings in correlated, quasi two-dimensional iridates

Abstract

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