density functional theory

The model Hamiltonian assumed for the DFT and atomistic spin dynamics is demonstrated in Figure 1 above. The experimental spin configuration of Ni3TeO6 was used. Due to the collinearity of the spins along the c-axis, we neglected anisotropic polar contributions and antisymmetric interactions.

Spin-polarized density functional theory (DFT) calculations were conducted by the use of VASP code, implementing the projector-augmented-wave (PAW) formalism to describe the electron-ion interactions, and the Generalized Gradient Approximation parametrized by Pedrew, Burke, and Ernzerhof (GGA-PBE), as well as the Local Density Approximation for the exchange-correlation potential.^1,2 In order to compensate the magnetic moments antiferromagnetically, the hexagonal unit cell was doubled along c-axis (60 atoms) and sampled by Automatic Gamma-centered, 40 grid mesh. The plane wave cutoff energy was set to 600 eV. Additional on-site Coulomb repulsion interactions were considered concurrently, within the rotationally invariant form of the GGA/LDA+U method (Liechtenstein approach),³ where a Hubbard repulsion term is added for the localized 3d electrons (U) and the exchange interaction (J), while the other orbitals are delocalized and treated by the conventional GGA/LDA approximation.

References

1. Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).

2. Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 77, 3865–3868 (1996).

3. Liechtenstein, A. I., Anisimov, V. I. & Zaanen, J. Density-functional theory and strong interactions: Orbital ordering in Mott-Hubbard insulators. Phys. Rev. B 52, R5467–R5470 (1995).