Unusual Electron Correlations in NaxCoO2 Due to the Spin-State Quasidegeneracy of Cobalt Ions

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F08%3A00027725" target="_blank" >RIV/00216224:14310/08:00027725 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Unusual Electron Correlations in NaxCoO2 Due to the Spin-State Quasidegeneracy of Cobalt Ions

Original language description

Recent studies exposed many remarkable properties of layered cobaltates NaxCoO2. Surprisingly, many-body effects have been found to increase at sodium-rich compositions of NaxCoO2 where one expects a simple, nearly free motion of the dilute S=1/2 holes doped into a band insulator NaCoO2. Here we discuss the origin of enigmatic correlations that turn a doped NaCoO2 into a strongly correlated electronic system. A minimal model including orbital degeneracy is proposed and its predictions are discussed. Themodel is based on a key property of cobalt oxides - the spin-state quasidegeneracy of CoO6 octahedral complex - which has been known, e.g., in the context of an unusual physics of LaCoO3 compound. Another important ingredient of the model is the 90 Co-O-Co bonding in NaxCoO2 which allows nearest-neighbor t2g-eg hopping. This hopping introduces a dynamical mixture of electronic configurations t2g6,S=0 and t2g5eg1,S=1 of neighboring cobalt ions. We show that scattering of charge carriers

Czech name

Neobvyklé korelace elektronů v NaxCoO2 způsobené kvazidegenerovaností spinových stavů kobaltových iontů

Czech description

Recent studies exposed many remarkable properties of layered cobaltates NaxCoO2. Surprisingly, many-body effects have been found to increase at sodium-rich compositions of NaxCoO2 where one expects a simple, nearly free motion of the dilute S=1/2 holes doped into a band insulator NaCoO2. Here we discuss the origin of enigmatic correlations that turn a doped NaCoO2 into a strongly correlated electronic system. A minimal model including orbital degeneracy is proposed and its predictions are discussed. Themodel is based on a key property of cobalt oxides - the spin-state quasidegeneracy of CoO6 octahedral complex - which has been known, e.g., in the context of an unusual physics of LaCoO3 compound. Another important ingredient of the model is the 90 Co-O-Co bonding in NaxCoO2 which allows nearest-neighbor t2g-eg hopping. This hopping introduces a dynamical mixture of electronic configurations t2g6,S=0 and t2g5eg1,S=1 of neighboring cobalt ions. We show that scattering of charge carriers

Type

J_x - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)

CEP classification

BM - Solid-state physics and magnetism

OECD FORD branch

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Project

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Continuities

Z - Vyzkumny zamer (s odkazem do CEZ)

Publication year

2008

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Progress of Theoretical Physics Supplement

ISSN

0375-9687

e-ISSN

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Volume of the periodical

176

Issue of the periodical within the volume

1

Country of publishing house

JP - JAPAN

Number of pages

27

Pages from-to

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UT code for WoS article

000263348100005

EID of the result in the Scopus database

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