Metal-insulator transition in composition-tuned nickel oxide films

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid-State Chemistry

Background:

• Solid solutions of Nd1-xLaxNiO3 exhibit intriguing electronic and magnetic properties.
• Understanding phase transitions in these materials is crucial for their technological applications.

Purpose of the Study:

• To investigate the 0 K phase transitions in Nd1-xLaxNiO3 thin films.
• To correlate structural, electronic, and magnetic properties with composition (x).

Main Methods:

• Thin film growth of Nd1-xLaxNiO3.
• Experimental characterization: Raman spectroscopy, scanning transmission electron microscopy, muon spin rotation (µSR).
• Theoretical calculations: Density Functional Theory (DFT) and DFT combined with Dynamical Mean Field Theory (DMFT).

Main Results:

• A discontinuous insulator-metal transition was observed at low temperature for x = 0.2.
• This transition was not accompanied by a discontinuous global structural change.
• DFT and DFT+DMFT calculations predicted a 0 K first-order transition around this composition.
• µSR measurements indicated non-static magnetic moments, potentially related to phase coexistence.

Conclusions:

• The study reveals a first-order insulator-metal transition in Nd1-xLaxNiO3 thin films at a specific composition.
• Theoretical calculations support the experimental findings of a 0 K transition and suggest phase coexistence.
• The observed magnetic moments are consistent with the first-order nature of the transition and phase coexistence.