Elucidating correlation-driven insulating state in an effective spin-½ antiferromagnet NdVO₄

Area of Science:

• Quantum Materials
• Condensed Matter Physics
• Rare-Earth Chemistry

Background:

• The J_eff= ½ state arises from the interplay of strong electronic correlations (U), spin-orbit coupling (SOC), and crystal field splitting.
• Rare-earth based materials are promising platforms for exploring quantum phenomena due to their unique electronic structures.

Purpose of the Study:

• To establish experimental and theoretical evidence for a J_eff= ½ state in the three-dimensional spin system NdVO₄.
• To investigate the role of SOC and electronic correlations in driving this state and its magnetic properties.
• To assess NdVO₄ as a potential U-driven correlated Mott insulator.

Main Methods:

• Magnetic measurements to identify signatures of the SOC-driven J_eff= ½ state and antiferromagnetic (AFM) interactions.
• Heat capacity measurements to determine the ordering temperature of the AFM state.
• Total energy calculations using density functional theory (DFT) with and without SOC and U to model electronic structure and correlations.

Main Results:

• Experimental evidence confirms a J_eff= ½ state in NdVO₄, exhibiting AFM interactions between Nd³⁺ moments.
• Heat capacity data reveals AFM ordering below 0.8 K and an entropy release of Rln2 around 4 K, consistent with a J_eff= ½ state.
• DFT calculations highlight the crucial role of SOC in establishing the J_eff= ½ state and AFM correlations, while electron-electron correlations (U) contribute to the insulating nature.

Conclusions:

• NdVO₄ hosts a J_eff= ½ state driven by SOC and electronic correlations, exhibiting antiferromagnetic ordering.
• The material's properties align with theoretical predictions, confirming the significance of SOC and U.
• NdVO₄ is identified as a promising candidate for a U-driven correlated Mott insulator, relevant for quantum materials research.