In a combined experimental and theoretical study, we investigate the properties of Sr2Ir1−xRhxO4. From the branching ratios of the L-edge isotropic x-ray absorption spectra, we determine that the spin-orbit coupling is remarkably independent of x for both iridium and rhodium sites. DFT+U calculations show that the doping is close to isoelectronic and introduces impurity bands of predominantly rhodium character close to the lower Hubbard band. Overlap of these two bands leads to metallic behavior. Since the low-energy states for xjeff=1/2 character, we suggest that the electronic properties of this material can be described by an inhomogeneous Hubbard model, where the on-site energies change due to local variations in the spin-orbit interaction strength combined with additional changes in binding energy.

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Published in Physical Review B, v. 92, no. 8, article 081114, p. 1-5.

©2015 American Physical Society

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Work at Argonne National Laboratory was supported by the US DOE, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. M.v.V. was supported by the US Department of Energy (DOE), Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. DE-FG02-03ER46097 and NIU’s Institute for Nanoscience, Engineering, and Technology. The computational work was partially performed at NERSC, which is supported by the US DOE Contract No. DE-AC02-05CH11231. Computational resources were partly supported by the National Institute of Supercomputing and Networking/Korea Institute of Science and Technology Information with supercomputing resources including technical support (Grant No. KSC-2013-C2-23). J.H.S. and M.J.H were supported by Basic Science Research Program through NRF (2014R1A1A2057202) and by Samsung Advanced Institute of Technology (SAIT). H.-S.K. was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant No. 2013R1A6A3A01064947). The work at the University of Kentucky was supported by NSF via Grant No. DMR- 1265162.

supplemental.pdf (176 kB)
Technical details regarding experiment and calculations.