From hidden metal-insulator transition to Planckian-like dissipation by tuning disorder in a nickelate

TL;DR

This study investigates how tuning disorder via oxygen content in NdNiO₃ films induces a transition from insulating to metallic states, revealing Planckian-like dissipation consistent with recent theoretical models.

Contribution

It demonstrates the emergence of linear resistivity and Planckian dissipation in nickelate films through controlled disorder tuning, linking experimental observations to theoretical predictions.

Findings

Hidden metal-insulator transition in oxygen-deficient NdNiO₃

Linear temperature dependence of resistivity in the metallic state

Resistivity scattering rate proportional to temperature, consistent with Planckian dissipation

Abstract

Heavily oxygen deficient NdNiO$_3$ (NNO) films, which are insulating due to electron localization, contain pristine regions that undergo a hidden metal-insulator transition. Increasing oxygen content increases the connectivity of the metallic regions and the metal-insulator transition is first revealed, upon reaching the percolation threshold, by the presence of hysteresis. Only upon further oxygenation is the global metallic state (with a change in the resistivity slope) eventually achieved. It is shown that sufficient oxygenation leads to linear temperature dependence of resistivity in the metallic state, with a scattering rate directly proportional to temperature. Despite the known difficulties to establish the proportionality constant, the experiments are consistent with a relationship 1/$\tau$= $\alpha k_B T/\hbar$, with $\alpha$ not far from unity. These results could provide experimental support for recent theoretical predictions of disorder in a two-fluid model as a possible origin of Planckian dissipation.