Orbital Engineering in Nickelate Heterostructures Driven by Anisotropic Oxygen Hybridization rather than Orbital Energy Levels

G. Fabbris, D. Meyers, J. Okamoto, J. Pelliciari, A. S. Disa, Y. Huang, Z.-Y. Chen, W. B. Wu, C. T. Chen, S. Ismail-Beigi, C. H. Ahn, F. J. Walker, D. J. Huang, T. Schmitt, and M. P. M. Dean
Phys. Rev. Lett. 117, 147401 – Published 30 September 2016
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Abstract

Resonant inelastic x-ray scattering is used to investigate the electronic origin of orbital polarization in nickelate heterostructures taking LaTiO3LaNiO33×(LaAlO3), a system with exceptionally large polarization, as a model system. We find that heterostructuring generates only minor changes in the Ni 3d orbital energy levels, contradicting the often-invoked picture in which changes in orbital energy levels generate orbital polarization. Instead, O K-edge x-ray absorption spectroscopy demonstrates that orbital polarization is caused by an anisotropic reconstruction of the oxygen ligand hole states. This provides an explanation for the limited success of theoretical predictions based on tuning orbital energy levels and implies that future theories should focus on anisotropic hybridization as the most effective means to drive large changes in electronic structure and realize novel emergent phenomena.

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  • Received 17 March 2016

DOI:https://doi.org/10.1103/PhysRevLett.117.147401

© 2016 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

G. Fabbris1,*, D. Meyers1, J. Okamoto2, J. Pelliciari3, A. S. Disa4, Y. Huang3, Z.-Y. Chen2, W. B. Wu2, C. T. Chen2, S. Ismail-Beigi4,5, C. H. Ahn4,5, F. J. Walker4, D. J. Huang2,6, T. Schmitt3, and M. P. M. Dean1,†

  • 1Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
  • 2National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
  • 3Research Department “Synchrotron Radiation and Nanotechnology”, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
  • 4Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
  • 5Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA
  • 6Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan

  • *gfabbris@bnl.gov
  • mdean@bnl.gov

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Vol. 117, Iss. 14 — 30 September 2016

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