Mott and pseudogap localization in pressurized NbO2

Abstract

We present a detailed study of correlation-induced electronic reconstruction in baddeleyite-type NbO 2 , a distorted ZrO 2-type structure that is found at pressures above 8.0 GPa. Based on density-functional plus dynamical mean-field theory (DFT+DMFT), we stress the importance of multiorbital Coulomb interactions in concert with first-principles band-structure calculations for a consistent understanding of emergent Mottness and pseudogap behavior in pressurized NbO 2 and related d 1 systems. After a proper treatment of multiorbital electron-electron interactions, we find a nearly universal Mott behavior for the peak position of the lower Hubbard band that is independent of crystal-and band-structure details. We explain the nature of the metalpseudogap-insulator transition to be seen in experiment, showing a first-order transition between two metallic states: a correlated metal and a pseudogap state with a deep density of states at the Fermi level. This emergent pseudogap phenomena is expected to play a central role toward quantum criticality in pressurized NbO 2 .

All-t2g Electronic Orbital Reconstruction of Monoclinic MoO2 Battery Material

“…Extensions of the single-site DMFT scheme to explicitly includes inter-site interactions, based, for example, on cluster DMFT approaches, may be considered to describe dynamical dimer-dimer correlations in MoO 2 and related materials. Nonetheless, the good agreement between the frequency dependence of the self-energy (imaginary and real parts) we have recently derived for baddeleyite-type NbO 2 [28] and that of the distorted, body-centered tetragonal (bct) NbO 2 crystal obtained using cluster DFT+DMFT calculations [29], fully qualifies single-site DFT+DMFT approximation for the study of the electrodynamic behaviour of MoO 2 battery material. Here, one-particle LDA density-of-states are computed using the non-fully relativistic version of the PY-LMTO code [30].…”

Mott localization in the van der Waals crystal CrI3 : A GGA+DMFT study

“…The MO-IPT scheme is computationally very efficient, with real frequency output at zero and finite temperatures [41], enabling the study of electronic structure reconstruction and transport properties of real materials with different magnetically ordered states and superconducting phase instabilities. Our real frequency MO-IPT scheme [40] has a proven record of good semiquantitative agreements with experiment for a range of correlated materials, and as shown recently it gives results for the spectral functions and self-energies in qualitatively accord with numerical exact continuous-time quantum Monte Carlo (CT-QMC) calculations [42,43], in spite of the fact that fully charged self-consistent DFT+DMFT calculations are presently unreachable within our perturbative treatment. In view of this, below we focus on the correlated spectral functions of paramagnetic CrI 3 bulk crystal and leave the extension of our approach as well as the derivation of the Mott-localized DFT+DMFT band structure for a future work.…”

Interplay of electric field and disorder in Dirac liquid silicene

“…This perturbative, many-particle scheme has a proven record of describing MO electronic correlations in broad pband systems [18,[30][31][32][33] and unconventional electronic structure reconstruction induced by dynamical quantum fluctuations in strongly correlated electron systems [34,35]. The MO-IPT scheme is computationally very efficient, with real frequency output at zero and finite temperatures, enabling the study of electronic structure reconstruction of real materials, and as shown recently it gives results for the spectral functions and self-energies in qualitatively accord with numerical exact continuos-time quantum Monte Carlo (CT-QMC) calculations [53,54].…”