Assessing the performance of the random phase approximation for exchange and superexchange coupling constants in magnetic crystalline solids

Abstract

The random phase approximation (RPA) for total energies has previously been shown to provide a qualitatively correct description of static correlation in molecular systems, where density functional theory (DFT) with local functionals are bound to fail. This immediately poses the question of whether the RPA is also able to capture the correct physics of strongly correlated solids such as Mott insulators. Due to strong electron localization, magnetic interactions in such systems are dominated by superexchange, which in the simplest picture can be regarded as the analog of static correlation for molecules. In this paper, we investigate the performance of the RPA for evaluating both superexchange and direct exchange interactions in the magnetic solids NiO, MnO, Na 3 Cu 2 SbO 6 , Sr 2 CuO 3 , Sr 2 CuTeO 6 , and a monolayer of CrI 3 , which were chosen to represent a broad variety of magnetic interactions. It is found that the RPA can accurately correct the large errors introduced by Hartree-Fock, independent of the input orbitals used for the perturbative expansion. However, in most cases, accuracies similar to RPA can be obtained with DFT+U, which is significantly simpler from a computational point of view.

High-throughput computational screening for two-dimensional magnetic materials based on experimental databases of three-dimensional compounds

“…The magnetic properties of possible candidate 2D materials are investigated using first principles Heisenberg models derived from DFT 2,[30][31][32]36 . In particular, if a 2D candidate material has a magnetic ground state we model the magnetic properties by the Hamiltonian…”

Discovering two-dimensional topological insulators from high-throughput computations

“…The exchange, and anisotropy constants J, A, and B can be obtained from first principles calculations combined with an energy mapping scheme that assumes magnetic moments to be located on transition metal atoms. 28,64 Since the magnetic structure is typically isotropic in the plane of the material a minimal requirement for magnetic order at finite temperatures is an out-of-plane easy axis. For the magnetic materials in Tab.…”

Orbitally-resolved ferromagnetism of monolayer CrI3

“…On the theory side, a large number of studies was devoted to a microscopic analysis of magnetism in 2D CrI 3 and its analogues [17][18][19][20][21][22][23][24]. Most of them were based on first-principles calculations (density functional theory and beyond) with direct mapping on the Heisenberg model.…”