Optical signatures of spin-orbit exciton in bandwidth-controlled Sr2IrO4 epitaxial films via high-concentration Ca and Ba doping
SCIE
SCOPUS
- Title
- Optical signatures of spin-orbit exciton in bandwidth-controlled Sr2IrO4 epitaxial films via high-concentration Ca and Ba doping
- Authors
- Souri, M.; Kim, B.H.; Gruenewald, J.H.; Connell, J.G.; Thompson, J.; Nichols, J.; Terzic, J.; Min, B.I.; Cao, G.; Brill, J.W.; Seo, A.
- Date Issued
- 2017-06
- Publisher
- AMER PHYSICAL SOC
- Abstract
- We have investigated the electronic and optical properties of (Sr1-xCax)2IrO4 (x=0-0.375) and (Sr1-yBay)2IrO4 (y=0-0.375) epitaxial thin films, in which the bandwidth is systematically tuned via chemical substitutions of Sr ions by Ca and Ba. Transport measurements indicate that the thin-film series exhibits insulating behavior, similar to the Jeff=1/2 spin-orbit Mott insulator Sr2IrO4. As the average A-site ionic radius increases from (Sr1-xCax)2IrO4 to (Sr1-yBay)2IrO4, optical conductivity spectra in the near-infrared region shift to lower energies, which cannot be explained by the simple picture of well-separated Jeff=1/2 and Jeff=3/2 bands. We suggest that the two-peak-like optical conductivity spectra of the layered iridates originates from the overlap between the optically forbidden spin-orbit exciton and the intersite optical transitions within the Jeff=1/2 band. Our experimental results are consistent with this interpretation as implemented by a multiorbital Hubbard model calculation: namely, incorporating a strong Fano-like coupling between the spin-orbit exciton and intersite d-d transitions within the Jeff=1/2 band. ? 2017 American Physical Society.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/50485
- DOI
- 10.1103/PhysRevB.95.235125
- ISSN
- 2469-9950
- Article Type
- Article
- Citation
- Physical Review b, vol. 95, no. 23, page. 235125, 2017-06
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