Mott transition of MnO under pressure: A comparison of correlated band theories

Abstract

The electronic structure, magnetic moment, and volume collapse of MnO under pressure are obtained from four different correlated band theory methods; local density approximation+ Hubbard U ͑LDA+ U͒, pseudopotential self-interaction correction ͑pseudo-SIC͒, the hybrid functional ͑combined local exchange plus Hartree-Fock exchange͒, and the local spin density SIC ͑SIC-LSD͒ method. Each method treats correlation among the five Mn 3d orbitals ͑per spin͒, including their hybridization with three O 2p orbitals in the valence bands and their changes with pressure. The focus is on comparison of the methods for rocksalt MnO ͑neglecting the observed transition to the NiAs structure in the 90-100 GPa range͒. Each method predicts a first-order volume collapse, but with variation in the predicted volume and critical pressure. Accompanying the volume collapse is a moment collapse, which for all methods is from high-spin to low-spin ͑ 5 2 → 1 2 ͒ , not to nonmagnetic as the simplest scenario would have. The specific manner in which the transition occurs varies considerably among the methods: pseudo-SIC and SIC-LSD give insulator-to-metal, while LDA+ U gives insulator-toinsulator and the hybrid method gives an insulator-to-semimetal transition. Projected densities of states above and below the transition are presented for each of the methods and used to analyze the character of each transition. In some cases the rhombohedral symmetry of the antiferromagnetically ordered phase clearly influences the character of the transition.

Spin crossover in theCsFeII[CrIII(CN)Middlemiss1, Portinari2, Grey3 et al. 2010Phys. Rev. B263220View full textAdd to dashboardCite

“…46 The applications of screened hybrid functionals to solids 47 are also worthy of note. The HSE screened hybrid was found to provide a reasonable description of the pressure-induced Mott transition in MnO, 48 of the Jahn-Teller effect in Mndoped GaN, 49 of the electronic and structural properties of the O vacancy in TiO 2 , 50 and of the band gaps and lattice parameters in a wide range of materials. 51 Central to all of these findings is the notion that hybrid functionals offer a systematic means by which to improve the description of materials bearing strongly correlated electrons.…”

Study of the volume and spin collapse in orthoferriteLuFeO3usingLDA+U

“…Recent LDA+U calculations on MnO give a similar conclusions, although the LS state obtained in this work seems to be less intuitive. 6 However we emphasize here the limitation of our work which does not contains fluctuations. These fluctuations could easily make the system metallic as has been shown recently in MnO.…”

“…6), the LDA+U method, which takes into account the strong correlations in the atomic limit, is able to describe these two phases. The density of states (DOS) of the HS and LS phase -at a volume belonging to their individual stability range -are shown on FIG.…”

“…4,5,6,7). These high pressure regions could be reached because of the development of the diamond anvil cell (DAC) 8 on the experimental side.…”

Enhanced Half-Metallicity in Edge-Oxidized Zigzag Graphene Nanoribbons

“…The electronic structures were then re-evaluated using the screened exchange hybrid density functional, HSE, 47,48 which has been tested in a wide variety of materials and has been shown to accurately reproduce experimental band gaps 49,50 and first and second optical excitation energies in metallic and semiconducting SWNTs. 51,52 Furthermore, the inclusion of shortrange exact-exchange in the HSE functional makes it suitable to treat electronic localization effects 53,54,55,56,57 which are known to be important in this type of materials. 18,19,20,21,22,23,24,25,26,27,28,37,58,59,60,61,62,63 We start by studying the relative stability of the different oxidized ribbons.…”