Electronic structure and magnetic properties of the effective spin J eff = 1 2 two-dimensional triangular lattice K 3 Yb (VO4)2

We report the structural, magnetic, specific heat, and electronic structure studies of the material , which has two-dimensional triangular layers constituted by rare-earth magnetic ions. Magnetic susceptibility data show the absence of magnetic long-range order down to . No bifurcation is observed between zero-field-cooled and field-cooled magnetic susceptibility data, ruling out the possibility of spin-glassiness down to . From the fit to magnetic susceptibility data with Curie-Weiss law in the low-temperature region, the observed Curie-Weiss temperature is about , implying an antiferromagnetic coupling between the ions. Magnetic field-dependent specific heat fits well with two-level Schottky behavior. The analysis of magnetization and specific heat data confirms that the ion hosts the effective spin state. To provide a microscopic understanding of the ground state nature of the titled material, we carried out state-of-the-art first-principles calculations based on density functional theory Hubbard U and density functional theory dynamical mean-field theory approaches. Our calculations reveal that the system belongs to the novel class of spin-orbit driven Mott Hubbard insulators and possesses large in-plane magnetocrystalline anisotropy.