Abstract
The mixing of orbital and spin character in the wave functions of the 5d 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 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 first such measurements for both parent and electron-doped Sr2IrO4. 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 (Sr1-xLax)2IrO4 and constrain the couplings of the phonons to magnetic and charge order.
| Original language | English |
|---|---|
| Article number | 085131 |
| Journal | Physical Review B |
| Volume | 100 |
| Issue number | 8 |
| DOIs | |
| State | Published - Aug 19 2019 |
| Externally published | Yes |
Funding
C.D.D. thanks A. Togo for assistance with the phonopy calculations. C.D.D. was supported by the Engineering and Physical Sciences Research Council (EPSRC) Centre for Doctoral Training in the Advanced Characterisation of Materials under Grant No. EP/L015277/1. The IXS measurements were supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Early Career Award Program under Award No. 1047478. The DFT calculations were carried out using high-performance computing resources at Moscow State University [54] . Work at Brookhaven National Laboratory was supported by the U.S. DOE, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-SC00112704. Work at UCL was supported by the EPSRC under Grants No. EP/N027671/1 and No. EP/N034872/1. Work at Ural Federal University was supported by the Russian Science Foundation under Grant No. 18-12-00185. G.C. was supported by the U.S. National Science Foundation under Grant No. DMR-1712101. The IXS experiments were performed at beamline BL43LXU at the SPring-8 synchrotron with the approval of RIKEN under Proposal No. 20180059. C.D.D. thanks A. Togo for assistance with the phonopy calculations. C.D.D. was supported by the Engineering and Physical Sciences Research Council (EPSRC) Centre for Doctoral Training in the Advanced Characterisation of Materials under Grant No. EP/L015277/1. The IXS measurements were supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Early Career Award Program under Award No. 1047478. The DFT calculations were carried out using high-performance computing resources at Moscow State University . Work at Brookhaven National Laboratory was supported by the U.S. DOE, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-SC00112704. Work at UCL was supported by the EPSRC under Grants No. EP/N027671/1 and No. EP/N034872/1. Work at Ural Federal University was supported by the Russian Science Foundation under Grant No. 18-12-00185. G.C. was supported by the U.S. National Science Foundation under Grant No. DMR-1712101. The IXS experiments were performed at beamline BL43LXU at the SPring-8 synchrotron with the approval of RIKEN under Proposal No. 20180059.