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

Abstract

The Jeff = ½ state: a result of interplay of strong electronic correlations (U) with spin-orbit coupling (SOC) and crystal field splitting, offers a platform in the research of quantum materials. In this context, 4f rare-earth based materials offer a fertile playground. Here, strong experimental and theoretical evidences for a Jeff = ½ state is established in a 3D spin system NdVO4. Magnetic measurements show the signatures of a SOC driven Jeff = ½ state along with the presence of antiferromagnetic (AFM) interaction between Nd3+ moments, whereas, heat capacity reveals the presence of an AFM ordering around 0.8 K, within this state. An entropy of Rln2 (equivalent to J = ½) is released around 4 K which implies the presence of Jeff = ½ state at low temperatures. Total energy calculations within the DFT framework reflect the central role of SOC in driving the Nd3+ ions to host such a state with AFM correlations between them, which is in agreement with experimental results. Further, DFT + SOC calculations with and without the inclusion of U, points that electron-electron correlations give rise to the insulating state making NdVO4 a potential candidate for U-driven correlated Mott insulator.