β-Cu2V2O7: A spin-1

Abstract

We report on band structure calculations and a microscopic model of the low-dimensional magnet β-Cu2V2O7. Magnetic properties of this compound can be described by a spin-1 2 anisotropic honeycomb lattice model with the averaged couplingJ1 = 60 − 66 K. The low symmetry of the crystal structure leads to two inequivalent couplings J1 and J ′ 1 , but this weak spatial anisotropy does not affect the essential physics of the honeycomb spin lattice. The structural realization of the honeycomb lattice is highly non-trivial: the leading interactions J1 and J ′ 1 run via double bridges of VO4 tetrahedra between spatially separated Cu atoms, while the interactions between structural nearest neighbors are negligible. The non-negligible inter-plane coupling J ⊥ ≃ 15 K gives rise to the long-range magnetic ordering at TN ≃ 26 K. Our model simulations improve the fit of the magnetic susceptibility data, compared to the previously assumed spin-chain models. Additionally, the simulated ordering temperature of 27 K is in remarkable agreement with the experiment. Our study evaluates β-Cu2V2O7 as the best available experimental realization of the spin-1 2 Heisenberg model on the honeycomb lattice. We also provide an instructive comparison of different band structure codes and computational approaches to the evaluation of exchange couplings in magnetic insulators.

Frustrated couplings between alternating spin-12chains in AgVOAsO4

“…We also applied different double-counting correction (DCC) schemes, aroundmean-field (AMF) and fully-localized-limit (FLL), since the choice between the two is known to affect exchange couplings in Cu +2 compounds. 5,41,42 Surprisingly, the exchange couplings in AgVOAsO 4 are largely insensitive to the DCC, whereas the change in U d leads to a typical evolution of J's (see, e.g., Ref. 27).…”

Unusual ferromagnetic superexchange in CdVO3: The role of Cd

“…Therefore, the DFT+U parameters U d and J d are generally different from U eff and J eff in the Hubbard model. 39,40 The second feature is the doublecounting-correction (DCC) scheme that subtracts part of the Coulomb energy already contained in LSDA, and enables the self-consistent procedure. Depending on the filling of individual d orbitals, the DCC is applied in either around-mean-field (AMF) or fully-localized-limit (FLL) fashions.…”

Field-induced evolution of magnetic ordering in the quantum spin system (CuBr)Sr2Nb3O10with aRitter1, Yusuf2, Bera3 et al. 2013Phys. Rev. B6120View full textAdd to dashboardCite

“…[1][2][3][4][5][6] Originally described in P 4/mmm, 7,8 the crystal structure of these compounds is characterized by square lattices of Cu 2+ ions in CuX-Halide layers separated by n slabs of nonmagnetic corner-sharing BO 6 octahedra. Interest in these compounds was stimulated as the compounds were believed to represent possible examples for the frustrated two-dimensional (2D) S = 1 /2 square lattice J 1 -J 2 model.…”