Spin-orbit coupling effects on spin-phonon coupling in Cd2Os2O7
arXiv:2010.10684 · doi:10.1103/PhysRevB.102.201101
Abstract
Spin-orbit coupling (SOC) is essential in understanding the properties of 5d transition metal compounds, whose SOC value is large and almost comparable to other key parameters. Over the past few years, there have been numerous studies on the SOC-driven effects of the electronic bands, magnetism, and spin-orbit entanglement for those materials with a large SOC. However, it is less studied and remains an unsolved problem in how the SOC affects the lattice dynamics. We, therefore, measured the phonon spectra of 5d pyrochlore Cd2Os2O7 over the full Brillouin zone to address the question by using inelastic x-ray scattering (IXS). Our main finding is a visible mode-dependence in the phonon spectra, measured across the metal-insulator transition at 227 K. We examined the SOC strength dependence of the lattice dynamics and its spin-phonon (SP) coupling, with first-principle calculations. Our experimental data taken at 100 K are in good agreement with the theoretical results obtained with the optimized U = 2.0 eV with SOC. By scaling the SOC strength and the U value in the DFT calculations, we demonstrate that SOC is more relevant than U to explaining the observed mode-dependent phonon energy shifts with temperature. Furthermore, the temperature dependence of the phonon energy can be effectively described by scaling SOC. Our work provides clear evidence of SOC producing a non-negligible and essential effect on the lattice dynamics of Cd2Os2O7 and its SP coupling.
arXiv comment12 pages, 5 figures, accepted for publication at Rapid Communication in Physical Review B
References in corpus (13)
- Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
- Correlated quantum phenomena in the strong spin-orbit regime
- Tetrahedral Magnetic Order and the Metal-Insulator Transition in the Pyrochlore Lattice of Cd2Os2O7
- Spin model of magnetostrictions in multiferroic Mn perovskites
- Spontaneous decays of magneto-elastic excitations in noncollinear antiferromagnet (Y,Lu)MnO3
- Emergent excitation at the magnetic metal-insulator transition in the pyrochlore osmate Cd2Os2O7
- Noncollinear magnetism and spin-orbit coupling in 5d pyrochlore oxide Cd2Os2O7
- Magnetic state of pyrochlore Cd2Os2O7 emerging from strong competition of ligand distortions and longer-range crystalline anisotropy
- Hybridization and Decay of Magnetic Excitations in two-dimensional Triangular Lattice Antiferromagnets
- Introduction to High-Resolution Inelastic X-Ray Scattering
- Renormalization of spin excitations in hexagonal HoMnO3 by magnon-phonon coupling
- Spin and orbital dynamics through the metal-to-insulator transition in CdOsO probed with high-resolution RIXS
- Lifshitz metal-insulator transition induced by the all-in/all-out magnetic order in the pyrochlore oxide Cd2Os2O7