Dichotomous electronic system in a bilayer Ni1+ nickelate
Abstract
"Infinite layer" nickelates cal RNiO2 (cal R=rare earth), having empty apical O sites, become superconducting upon hole doping, stimulating research into the related sequence Ndn+1Ni+pnO2n+2, formal charge state p=1+1/n, n=2,3,4,...., with the n=5 member being found to be superconducting. The two layer system La3Ni2O7−δ, with δ=0,1/2,1 (p=2.5,2,1.5) approaches the peak in the nickelate superconducting dome but shows no superconductivity. Newly reported La3Ni2O5F reaches the Ni1+ goal while, as we show, introducing a partially occupied electron band E*, based on an interstitial density that extends over the three open "apical" layers and leads to a single cylindrical electron Fermi surface giving self-doping. The commonly inert Ni dxz,dyz orbitals partner with interstitial E* to provide an incipient non-analytic Dirac point, with the critical point being reachable by pressure or further F insertion. The E* electron cylinder and the conventional Ni dpσ hole carriers combine to provide a two-fluid dichotomy of hole and electron quasiparticles, affecting normal state properties that should verify the dichotomous aspect of transport.
Related
- Electronic theory for scanning tunneling microscopy spectra in bilayer nickelate thin films
- Selective suppression of electronic orders via interlayer coupling in superconducting bilayer nickelate thin films
- Electronic Structure of Compressively Strained Bilayer Nickelate Thin Film
- Spectroscopic evidence of competing diagonal spin interactions and spin disproportionation in the bilayer nickelate La 3 Ni 2 O 7
- Observation of superconductivity-induced leading-edge gap in a bilayer nickelate
BibTeX
@misc{song2026dichotomous,
title = {{Dichotomous electronic system in a bilayer Ni$^1+$ nickelate}},
author = {Young-Joon Song and K. -W. Lee and W. E. Pickett},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2606.10564},
eprint = {2606.10564},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.10564},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Dichotomous electronic system in a bilayer Ni^1+ nickelate
AU - Young-Joon Song
AU - K. -W. Lee
AU - W. E. Pickett
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2606.10564
UR - https://arxiv.org/abs/2606.10564
AB - "Infinite layer" nickelates cal RNiO_2 (cal R=rare earth), having empty apical O sites, become superconducting upon hole doping, stimulating research into the related sequence Nd_n+1Ni^+p_nO_2n+2, formal charge state p=1+1/n, n=2,3,4,...., with the n=5 member being found to be superconducting. The two layer system La_3Ni_2O_7−δ, with δ=0,1/2,1 (p=2.5,2,1.5) approaches the peak in the nickelate superconducting dome but shows no superconductivity. Newly reported La_3Ni_2O_5F reaches the Ni^1+ goal while, as we show, introducing a partially occupied electron band E^*, based on an interstitial density that extends over the three open "apical" layers and leads to a single cylindrical electron Fermi surface giving self-doping. The commonly inert Ni d_xz,d_yz orbitals partner with interstitial E^* to provide an incipient non-analytic Dirac point, with the critical point being reachable by pressure or further F insertion. The E^* electron cylinder and the conventional Ni dpσ hole carriers combine to provide a two-fluid dichotomy of hole and electron quasiparticles, affecting normal state properties that should verify the dichotomous aspect of transport.
ER -