Mott Transition of MnO under Pressure: A Comparison of Correlated Band Theories

Journal Article · Sun Jan 01 04:00:00 EST 2006 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.74.195110· OSTI ID:931264

Kasinathan, Deepa ^[1]; Kunes, Jan ^[2]; Koepernik, K ^[3]; Diaconu, Cristian V ^[4]; Martin, Richard L ^[4]; Prodan, Ionut ^[5]; Scuseria, Gustavo E ^[5]; Spaldin, Nicola ^[6]; Petit, Leon ^[7]; Schulthess, Thomas C ^[7]; Pickett, W. E. ^[1]

---

1. University of California, Davis
2. ASCR, Czech Republic
3. IFW Dresden
4. Los Alamos National Laboratory (LANL)
5. Rice University
6. University of California, Santa Barbara
7. ORNL

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+U), pseudopotential self-interaction correction (pseudo-SIC), the hybrid functional (combined local exchange plus Hartree-Fock exchange), and the local spin density SIC (SIC-LSD) method. Each method treats correlation among the five Mn 3d orbitals (per spin), 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 rock salt MnO (neglecting the observed transition to the NiAs structure in the 90-100 GPa range). 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){yields}(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-to-insulator 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.

• Research Organization: Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences; Center for Computational Sciences
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 931264
• Journal Information: Physical Review B, Journal Name: Physical Review B Vol. 74
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BAND THEORY
CRITICAL PRESSURE
ELECTRONIC STRUCTURE
MAGNETIC MOMENTS
MANGANESE OXIDES
PHASE TRANSFORMATIONS
PRESSURE DEPENDENCE
SPIN
SYMMETRY