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T→0 Metal-Insulator Transition in Bulk (La,R)NiO<sub>3</sub> (R = rare-earth) Nickelates: A Bond-Percolation Transition?

ORAL

Abstract

We report x-ray diffraction, electrical resistivity, and other data on bulk polycrystalline La1-xRxNiO3 (R=Y, Nd; x = 0-1) in efforts to test the prediction[1] of a universal T→0 Metal-Insulator (M-I) transition for all (La,R)NiO3 nearly-perovskite materials. The samples were prepared using a sol-gel precursor that was then subject to high oxygen pressure (150-200 bar), high temperature (950°C-1050°C) conditions, or high quasi-hydrostatic pressures using a hot piston-cylinder apparatus (2.0-2.5 GPa) at high temperatures (900°C-1000°C) for La1-xYxNiO3 (x > 0.2). A bond percolation model for a simple cubic lattice predicts a threshold doping concentration of only x = 0.29 to reduce the bond fraction to the percolation threshold, pc ≈ 0.249. The concentration-dependent conductivity trends lower than the theoretical predictions[2]. The correlated bond-breaking considered here may only slightly shift the percolation threshold, but the decrease in the conductance is more dramatic.

[1] Gregorio Ponti, et al. 2021 APS March Meeting, X43.14 (2021), Virtual.

[2] Scott Kirkpatrick, Rev. Mod. Phys. 45, 574 (1973).

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Presenters

  • Gregorio Ponti

    Department of Physics, University of Texas at Austin

Authors

  • Gregorio Ponti

    Department of Physics, University of Texas at Austin

  • Sara J Irvine

    Department of Physics, University of Texas at Austin

  • Holland Frieling

    Department of Physics, University of Texas at Austin

  • Lucas P Moynihan

    Department of Physics, University of Texas at Austin

  • Jonathan D. K. Tebo

    Department of Physics, University of Texas at Austin

  • Quinn Timmers

    Department of Physics, University of Texas at Austin

  • John T Markert

    Department of Physics, University of Texas at Austin, University of Texas at Austin