TY - JOUR
T1 - Mott transition and magnetic collapse in iron-bearing compounds under high pressure
AU - Leonov, I.
AU - Greenberg, E.
AU - Belov, M. P.
AU - Rozenberg, G. Kh
AU - Abrikosov, I. A.
N1 - Publisher Copyright:
© 2017 Informa UK Limited, trading as Taylor & Francis Group.
PY - 2017/4/3
Y1 - 2017/4/3
N2 - We discuss the electronic, magnetic, and related structural transitions in the iron-based Mott insulators under high pressures relevant to the Earth's lower mantle conditions. The paper focuses on the above-mentioned topics based primarily on our theoretical analysis and various experimental studies employing synchrotron X-ray diffraction,57Fe Mössbauer spectroscopy, and electrical transport measurements. We review the main theoretical tools employed for the analysis of the properties of materials with strongly interacting electrons and discuss the problems of theoretical description of such systems. In particular, we discuss a state-of-the-art method for calculating the electronic structure of strongly correlated materials, the DFT + DMFT method, which merges standard band-structure techniques (DFT) with dynamical mean-field theory of correlated electrons (DMFT). We employ this method to study the pressure-induced magnetic collapse in Mott insulators, such as wüstite (FeO), magnesiowüstite (Fe1-x Mgx)O (x=0.25 and 0.75) and goethite (FeOOH), and explore the consequences of the magnetic collapse for the electronic structure and phase stability of these materials. We show that the paramagnetic cubic B1-structured FeO and (Fe,Mg)O and distorted orthorhombic (Pnma) FeOOH exhibit upon compression a high- to low-spin (HS-LS) transition, which is accompanied by a simultaneous collapse of local moments. However, the HS-LS transition is found to have different consequences for the electronic properties of these compounds. For FeO and (Fe0.75 Mg0.25)O, the transition is found to be accompanied by a Mott insulator-to-metal phase transition. In contrast to that, both (Fe0.25 Mg0.75)O and FeOOH remain insulating up to the highest studied pressures, indicating that a Mott insulator to band insulator phase transition takes place. Our combined theoretical and experimental studies indicate a crossover between localized to itinerant moment behavior to accompany magnetic collapse of Fe ions.
AB - We discuss the electronic, magnetic, and related structural transitions in the iron-based Mott insulators under high pressures relevant to the Earth's lower mantle conditions. The paper focuses on the above-mentioned topics based primarily on our theoretical analysis and various experimental studies employing synchrotron X-ray diffraction,57Fe Mössbauer spectroscopy, and electrical transport measurements. We review the main theoretical tools employed for the analysis of the properties of materials with strongly interacting electrons and discuss the problems of theoretical description of such systems. In particular, we discuss a state-of-the-art method for calculating the electronic structure of strongly correlated materials, the DFT + DMFT method, which merges standard band-structure techniques (DFT) with dynamical mean-field theory of correlated electrons (DMFT). We employ this method to study the pressure-induced magnetic collapse in Mott insulators, such as wüstite (FeO), magnesiowüstite (Fe1-x Mgx)O (x=0.25 and 0.75) and goethite (FeOOH), and explore the consequences of the magnetic collapse for the electronic structure and phase stability of these materials. We show that the paramagnetic cubic B1-structured FeO and (Fe,Mg)O and distorted orthorhombic (Pnma) FeOOH exhibit upon compression a high- to low-spin (HS-LS) transition, which is accompanied by a simultaneous collapse of local moments. However, the HS-LS transition is found to have different consequences for the electronic properties of these compounds. For FeO and (Fe0.75 Mg0.25)O, the transition is found to be accompanied by a Mott insulator-to-metal phase transition. In contrast to that, both (Fe0.25 Mg0.75)O and FeOOH remain insulating up to the highest studied pressures, indicating that a Mott insulator to band insulator phase transition takes place. Our combined theoretical and experimental studies indicate a crossover between localized to itinerant moment behavior to accompany magnetic collapse of Fe ions.
KW - Mott metal–insulator transition
KW - Strong correlations
KW - high pressure
KW - spin-state transition
KW - transition metal oxides
UR - http://www.scopus.com/inward/record.url?scp=85018644749&partnerID=8YFLogxK
U2 - 10.1080/08957959.2017.1302445
DO - 10.1080/08957959.2017.1302445
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AN - SCOPUS:85018644749
SN - 0895-7959
VL - 37
SP - 96
EP - 118
JO - High Pressure Research
JF - High Pressure Research
IS - 2
ER -