Imaging and Harnessing Percolation at the Metal–Insulator Transition of NdNiO 3 Nanogaps

Jin Hong Lee (1) , Felix Trier (1) , Tom Cornelissen (1) , Daniele Preziosi (1) , Stéphane Fusil (1) , Karim Bouzehouane (1) , Sergio Valencia (2) , Manuel Bibes (1)

1 Laboratoire Albert Fert (ex-UMPhy Unité mixte de physique CNRS/Thales)
2 HZB - Helmholtz-Zentrum Berlin für Materialien und Energie GmbH = Helmholtz Centre Berlin for Materials and Energy = Centre Helmholtz de Berlin pour les matériaux et l'énergie

Keywords: metal-insulator transition, phase separation, domain percolation, nanodevice J.H.L. and F.T. contributed equally to this work. Competition between co-existing electronic phases in first-order phase transitions can lead to a sharp change in the resistivity as the material is subjected to small variations in the driving parameter, e.g., the temperature. One example of this phenomenon is the metal-insulator transition (MIT) in perovskite rare-earth nickelates. In such systems, reducing the transport measurement area to dimensions comparable to the domain size of insulating and metallic phases around the MIT should strongly influence the shape of the resistance-temperature curve. Here, we measure the temperature dependence of the local resistance and the nanoscale domain distribution of NdNiO3 areas between Au contacts gapped by 260 down to 40 nm. We find that a sharp resistance drop appears below the bulk MIT temperature at ~105 K, with an amplitude inversely scaling with the nanogap width. By using X-ray photoemission electron microscopy, we directly correlate the resistance drop with the emergence and coalescence of individual metallic domains at the nanogap. Our observation provides a direct insight into percolation at the MIT of rare-earth nickelates.

Domaines: Matière Condensée [cond-mat]

Jin Hong Lee, Felix Trier, Tom Cornelissen, Daniele Preziosi, Stéphane Fusil, et al.. Imaging and Harnessing Percolation at the Metal–Insulator Transition of NdNiO 3 Nanogaps. Nano Letters, 2019, ⟨10.1021/acs.nanolett.9b02815⟩. ⟨hal-02331430⟩