LDA+DMFTcomputation of the electronic spectrum of NiO

Abstract

The electronic spectrum, energy gap and local magnetic moment of paramagnetic NiO are computed by using the local density approximation plus dynamical mean-field theory (LDA+DMFT). To this end the noninteracting Hamiltonian obtained within the local density approximation (LDA) is expressed in Wannier functions basis, with only the five anti-bonding bands with mainly Ni 3d character taken into account. Complementing it by local Coulomb interactions one arrives at a material-specific many-body Hamiltonian which is solved by DMFT together with quantum MonteCarlo (QMC) simulations. The large insulating gap in NiO is found to be a result of the strong electronic correlations in the paramagnetic state. In the vicinity of the gap region, the shape of the electronic spectrum calculated in this way is in good agreement with the experimental x-rayphotoemission and bremsstrahlung-isochromat-spectroscopy results of Sawatzky and Allen. The value of the local magnetic moment computed in the paramagnetic phase (PM) agrees well with that measured in the antiferromagnetic (AFM) phase. Our results for the electronic spectrum and the local magnetic moment in the PM phase are in accordance with the experimental finding that AFM long-range order has no significant influence on the electronic structure of NiO.

First-principles modeling of localizeddstates with theGW@LDA+Uapproach

“…10,15,21,25,43,83,96,[112][113][114][115][116] The four compounds roughly fall into two classes: ͑1͒ MnO and NiO, for which standard band theory within LDA or GGA still predicts an insulating ground state when applied in the AFM-II phase but with significantly underestimated band gaps; ͑2͒ FeO and CoO, for which LDA and GGA give metallic ground states even in the AFM-II phase. 7 In this work we consider only the AFM-II phase.…”

Magnetic collapse and the behavior of transition metal oxides at high pressure

“…This obstacle can be overcome by employing, e.g., a state-of-the-art method for calculating the electronic structure of strongly correlated materials [density functional plus dynamical mean-field theory (DFT+DMFT)] [9,10]. It merges ab initio band-structure techniques, such as the local density approximation (LDA) or the generalized gradient approximation (GGA), with dynamical mean-field theory (DMFT) of correlated electrons [9], providing a good quantitative description of the electronic and lattice properties [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. In particular, this advanced theory makes it possible to determine the electronic structure and phase stability of paramagnetic correlated materials at finite temperatures, e.g., near a Mott insulator-metal transition [13][14][15][20][21][22][23][24][25][26][27][28].…”

“…In particular, this advanced theory makes it possible to determine the electronic structure and phase stability of paramagnetic correlated materials at finite temperatures, e.g., near a Mott insulator-metal transition [13][14][15][20][21][22][23][24][25][26][27][28]. The DFT+DMFT approach has been used to study the electronic and structural properties of correlated electron materials [11][12][13][14][15][16][17][18][19][20], including transition metal monoxides [22][23][24][25][26][27][28][29]. In practice, however, these calculations employed different approximations, resulting in various scenarios for the IMT.…”

“…It merges ab initio band-structure techniques, such as the local density approximation (LDA) or the generalized gradient approximation (GGA), with dynamical mean-field theory (DMFT) of correlated electrons [9], providing a good quantitative description of the electronic and lattice properties [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. In particular, this advanced theory makes it possible to determine the electronic structure and phase stability of paramagnetic correlated materials at finite temperatures, e.g., near a Mott insulator-metal transition [13][14][15][20][21][22][23][24][25][26][27][28]. The DFT+DMFT approach has been used to study the electronic and structural properties of correlated electron materials [11][12][13][14][15][16][17][18][19][20], including transition metal monoxides [22][23][24][25...…”

Continuous-pole-expansion method to obtain spectra of electronic lattice models

“…NiO is a prototypical material with strong electronic correlations that has been 245114-8 extensively studied both experimentally [34][35][36] and theoretically [37][38][39][40]. The experimental results from the literature for this compound are the next best thing compared to the exact solution of the impurity model of a multiband system.…”