Abstract
The mixing of orbital and spin character in the wave functions of the iridates has led to predictions of strong couplings among their lattice, electronic, and magnetic degrees of freedom. As well as realizing a novel spin-orbit assisted Mott-insulating ground state, the perovskite iridate has strong similarities with the cuprate , which on doping hosts a charge-density wave that appears intimately connected to high-temperature superconductivity. These phenomena can be sensitively probed through momentum-resolved measurements of the lattice dynamics, made possible by -resolution inelastic x-ray scattering. Here we report the first such measurements for both parent and electron-doped . We find that the low-energy phonon dispersions and intensities in both compounds are well described by the same nonmagnetic density functional theory calculation. In the parent compound, no changes of the phonons on magnetic ordering are discernible within the experimental resolution, and in the doped compound no anomalies are apparent due to charge-density waves. These measurements extend our knowledge of the lattice properties of ( and constrain the couplings of the phonons to magnetic and charge order.
- Received 24 April 2019
DOI:https://doi.org/10.1103/PhysRevB.100.085131
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