Manipulation of electronic structure via alteration of local orbital environment in [(SrIrO3)m,(SrTiO3)](m=1,2,and) superlattices

So Yeun Kim, Choong H. Kim, L. J. Sandilands, C. H. Sohn, J. Matsuno, H. Takagi, K. W. Kim, Y. S. Lee, S. J. Moon, and T. W. Noh
Phys. Rev. B 94, 245113 – Published 6 December 2016

Abstract

We investigated the electronic structure of [(SrIrO3)m,(SrTiO3)](m=1,2,and) superlattice (SL) thin films with optical spectroscopy and first principles calculations. Our optical results confirmed the existence of the Jeff=1/2 states in SL samples, similar to the bulk Ruddlesden-Popper series Srn+1IrnO3n+1 iridates. Apart from this similarity, in the SL samples, we observed red shifts of the characteristic optical excitations in the Jeff=1/2 state and an enhancement of the low-energy spectral weight, which implies a reduction in the effective electron correlation for bands near the Fermi energy. The density functional theory plus Coulomb interactions (DFT+U) calculations suggested that the SrTiO3 layer intervened between SrIrO3 layers in the SLs activated additional hopping channels between the Ir ions, thus increasing the bandwidth and reducing the effective strength of the correlations. This paper demonstrates that fabrication of iridium-based heterostructures can be used to finely tune electronic structures via alteration of their local orbital environments.

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  • Received 24 September 2016
  • Revised 10 November 2016

DOI:https://doi.org/10.1103/PhysRevB.94.245113

©2016 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

So Yeun Kim1,2, Choong H. Kim1,2, L. J. Sandilands1,2, C. H. Sohn1,2, J. Matsuno3, H. Takagi4,5, K. W. Kim6, Y. S. Lee7, S. J. Moon8,*, and T. W. Noh1,2

  • 1Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
  • 2Department of Physics & Astronomy, Seoul National University, Seoul 08826, Republic of Korea
  • 3RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
  • 4Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033, Japan
  • 5Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany
  • 6Department of Physics, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
  • 7Department of Physics, Soongsil University, Seoul 07027, Republic of Korea
  • 8Department of Physics, Hanyang University, Seoul 04763, Republic of Korea

  • *Corresponding author: soonjmoon@hanyang.ac.kr

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Vol. 94, Iss. 24 — 15 December 2016

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