Journal Article

PUBDB-2016-03122

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Low-energy description of the metal-insulator transition in the rare-earth nickelates

Subedi, A. (Corresponding author)Extern* ; Peil, O. E. ; Georges, A.

2015
APS College Park, Md.

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Please use a persistent id in citations: doi:10.1103/PhysRevB.91.075128

Abstract: We propose a simple theoretical description of the metal-insulator transition of rare-earth nickelates. Thetheory involves only two orbitals per nickel site, corresponding to the low-energy antibonding $e_g$ states. In themonoclinic insulating state, bond-length disproportionation splits the manifold of $e_g$ bands, corresponding to a modulation of the effective on-site energy. We show that, when subject to a local Coulomb repulsion $U$ and Hund’s coupling $J$, the resulting bond-disproportionated state is a paramagnetic insulator for a wide range of interaction parameters. Furthermore, we find that when $U − 3 J$ is small or negative, a spontaneous instability to bond disproportionation takes place for large enough $J$. This minimal theory emphasizes that a small or negativecharge-transfer energy, a large Hund’s coupling, and a strong coupling to bond disproportionation are the key factors underlying the transition. Experimental consequences of this theoretical picture are discussed.

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Contributing Institute(s):

1. Forschungsgruppe für strukturelle Dynamik (MPSD)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)
2. Q-MAC - Frontiers in Quantum Materials Control (319286) (319286)

Experiment(s):

1. No specific instrument

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Database coverage:
; ; ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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