Decisive Roles of Intersite Coulomb Interactions in Charge Ordered Systems

Abstract

Using ab initio approaches for extended Hubbard interactions coupled to phonons, we reveal that the intersite Coulomb interaction plays decisive roles in determining various distinctive phases of the paradigmatic charge ordered materials of Ba1−xKxAO3 (A = Bi and Sb). We demonstrated that all their salient doping dependent experiment features such as breathing instabilities, anomalous phonon dispersions, and transition between charge-density wave and superconducting states can be accounted very well if self-consistently obtained nearest neighbor Hubbard interaction are included, thus establishing a minimal criterion for reliable descriptions of spontaneous charge orders in solids.

Unraveling the effects of inter-site Hubbard interactions in spinel Li-ion cathode materials

“…Most importantly, the effect of inter-site Hubbard V interactions [36][37][38] has never been investigated in the spinel cathode materials; these interactions have been shown to be very important in other transition-metal (TM) oxides due to strong metal-ligand hybridization. [39][40][41][42][43][44][45][46][47][48][49] Herein, we present a fully first-principles study of the structural, electronic, magnetic, and electrochemical properties of the spinel cathode materials Li x Mn 2 O 4 and Li x Mn 1.5 Ni 0.5 O 4 (x = 0 and 1) using DFT with extended Hubbard functionals (DFT+U+V), 36 where the on-site U and inter-site V Hubbard parameters are computed unbiasedly and fully from firstprinciples using density-functional perturbation theory (DFPT) 50,51 in a basis of Lo ¨wdin-orthogonalized atomic orbitals. This avoids any empiricism and possible ambiguities of Hubbard-corrected DFT studies.…”

Unraveling the effects of inter-site Hubbard interactions in spinel Li-ion cathode materials

“…LiMn 1.5 Ni 0.5 O 4 the on-site Hubbard U parameter has been chosen empirically such that some experimental properties of interest are well reproduced; this is different from a fully first-principles-based approach and likely contributed to the spread of the reported results. Most importantly, the effect of inter-site Hubbard V interactions [36][37][38] has never been investigated in the spinel cathode materials; these interactions have been shown to be very important in other transition-metal (TM) oxides due to strong metal-ligand hybridization [39][40][41][42][43][44][45][46][47][48][49].…”