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arXiv · 1808.10861

Spin-gap and two-dimensional magnetic excitations in Sr2IrO4

S. Calder·D. M. Pajerowski·M. B. Stone·A. F. May
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Abstract

Time-of-flight inelastic neutron scattering measurements on Sr2IrO4 single crystals were performed to access the spin Hamiltonian in this canonical Jeff=1/2 spin-orbital Mott insulator. The momentum of magnetic scattering at all inelastic energies that were measured is revealed to be $L$-independent, indicative of idealized two-dimensional in-plane correlations. By probing the in-plane energy and momentum dependence up to ~80 meV we model the magnetic excitations and define a spin-gap of 0.6(1) meV. Collectively the results indicate that despite the strong spin-orbit entangled isospins an isotropic two-dimensional S=1/2 Heisenberg model Hamiltonian accurately describes the magnetic interactions, pointing to a robust analogy with unconventional superconducting cuprates.

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S. Calder, D. M. Pajerowski, M. B. Stone, A. F. May. 2018-08-31. Spin-gap and two-dimensional magnetic excitations in Sr2IrO4. https://doi.org/10.1103/physrevb.98.220402

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