Tuning the metal-insulator transition in NdNiO3 heterostructures via Fermi surface instability and spin-fluctuations

TL;DR

This study investigates how substrate-induced strain influences the electronic structure and metal-insulator transition in NdNiO3 thin films using ARPES, revealing the role of Fermi surface changes and spin fluctuations.

Contribution

It demonstrates how strain tuning modifies Fermi surface nesting and spin fluctuations, controlling the MIT in NdNiO3 heterostructures, a novel insight into electronic phase control.

Findings

Strain alters Fermi surface topology and nesting conditions.

Quasiparticle coherence is lost across the MIT in NNO/NGO.

Substrate-induced strain influences spin-fluctuation strength.

Abstract

We employed {\it in-situ} pulsed laser deposition (PLD) and angle-resolved photoemission spectroscopy (ARPES) to investigate the mechanism of the metal-insulator transition (MIT) in NdNiO$_3$ (NNO) thin films, grown on NdGaO$_3$(110) and LaAlO$_3$(100) substrates. In the metallic phase, we observe three dimensional hole and electron Fermi surface (FS) pockets formed from strongly renormalized bands with well-defined quasiparticles. Upon cooling across the MIT in NNO/NGO sample, the quasiparticles lose coherence via a spectral weight transfer from near the Fermi level to localized states forming at higher binding energies. In the case of NNO/LAO, the bands are apparently shifted upward with an additional holelike pocket forming at the corner of the Brillouin zone. We find that the renormalization effects are strongly anisotropic and are stronger in NNO/NGO than NNO/LAO. Our study reveals that substrate-induced strain tunes the crystal field splitting, which changes the FS properties, nesting conditions, and spin-fluctuation strength, and thereby controls the MIT via the formation of an electronic order parameter with Q$_{AF}\sim$(1/4, 1/4, 1/4$\pm$$\delta$).