Realistic many-body models for Manganese Monoxide under pressure

Abstract

In materials like transition metals oxides where electronic Coulomb correlations impede a description in terms of standard band-theories, the application of genuine many-body techniques is inevitable. Interfacing the realism of density-functional based methods with the virtues of Hubbard-like Hamiltonians, requires the joint ab initio construction of transfer integrals and interaction matrix elements (like the Hubbard U) in a localized basis set. In this work, we employ the scheme of maximally localized Wannier functions and the constrained random phase approximation to create effective low-energy models for Manganese monoxide, and track their evolution under external pressure. We find that in the low pressure antiferromagnetic phase, the compression results in an increase of the bare Coulomb interaction for specific orbitals. As we rationalized in recent model considerations [Phys. Rev. B 79, 235133 (2009)], this seemingly counter-intuitive behavior is a consequence of the delocalization of the respective Wannier functions. The change of screening processes does not alter this tendency, and thus, the screened on-site component of the interaction - the Hubbard U of the effective low-energy system - increases with pressure as well. The orbital anisotropy of the effects originates from the orientation of the orbitals vis-a-vis the deformation of the unit-cell. Within the high pressure paramagnetic phase, on the other hand, we find the significant increase of the Hubbard U is insensitive to the orbital orientation and almost exclusively owing to a substantial weakening of screening channels upon compression.

13 pages, 6 figures

References in corpus (6)

• Screened Coulomb interaction in the maximally localized Wannier basis
• Magnetic Moment Collapse-Driven Mott Transition in MnO
• Self-consistency over the charge-density in dynamical mean-field theory: a linear muffin-tin implementation and some physical implications
• Ab initio Derivation of Low-energy Model for Iron-Based Superconductors LaFeAsO and LaFePO
• Mott Transition of MnO under Pressure: Comparison of Correlated Band Theories
• Effective Coulomb interactions in solids under pressure

Cited by in corpus (2)

• Thermopower of correlated semiconductors : application to FeAs2 and FeSb2
• Ab initio Low-Dimensional Physics Opened Up by Dimensional Downfolding: Application to LaFeAsO