Momentum-resolved lattice dynamics of parent and electron-doped Sr 2 IrO 4

• Published in: Physical review. B 2019-08, Vol.100 (8), Article 085131
• Main Authors: Dashwood, C. D., Miao, H., Vale, J. G., Ishikawa, D., Prishchenko, D. A., Mazurenko, V. V., Mazurenko, V. G., Perry, R. S., Cao, G., de la Torre, A., Baumberger, F., Baron, A. Q. R., McMorrow, D. F., Dean, M. P. M.
• Format: Article
• Language: English
• Subjects: CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
• ISSN: 2469-9950; 2469-9969
• DOI: 10.1103/PhysRevB.100.085131

The mixing of orbital and spin character in the wavefunctions of the 5d iridates has led to predictions of strong couplings between their lattice, electronic and magnetic degrees of freedom. As well as realising a novel spin-orbit assisted Mott-insulating ground state, the perovskite iridate Sr2IrO4 has strong similarities with the cuprate La2CuO4, 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 meV-resolution inelastic x-ray scattering. Here we report the rst such measurements for both parent and electron-doped Sr2IrO4. We nd that the low-energy phonon dispersions and intensities in both compounds are well described by the same non-magnetic DFT calculation. In the parent compound, no changes of the phonons upon 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 (Sr1-xLax)2IrO4, and constrain the couplings of the phonons to magnetic and charge order.