Tuning of magnetic ground state of the spin-12square-lattice compound Zn2VO(PO4)2through chemical substitution

Abstract

Using first-principles density-functional-theory-based calculations, we derive the low-energy spin model of the compound Zn${}_{2}$VO(PO${}_{4}$)${}_{2}$, and $\frac{1}{4}$th Ti-substituted compound Zn${}_{8}$TiV${}_{3}$O${}_{4}$(PO${}_{4}$)${}_{8}$ which is yet to be synthesized. We compute the thermodynamics properties of the proposed spin models by the quantum Monte Carlo technique. For the pristine compound Zn${}_{2}$VO(PO${}_{4}$)${}_{2}$ our computed susceptibility is found to be in good agreement with the available experimental data and is in accordance with the earlier proposed spin model of the spin-$\frac{1}{2}$ antiferromagnetic square lattice. Upon Ti substitution, which may be viewed as $\frac{1}{4}$-spin depletion, the two-dimensional antiferromagnetic square-lattice behavior of the parent compound is found to be altered significantly, giving rise to spin-gap behavior. We hope that our work will stimulate further experimental studies on this compound.