Universität zu Köln

Streltsov, Sergey V. and Khomskii, Daniel I. (2014). Orbital-dependent singlet dimers and orbital-selective Peierls transitions in transition-metal compounds. Phys. Rev. B, 89 (16). COLLEGE PK: AMER PHYSICAL SOC. ISSN 1550-235X

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Abstract

We show that in transition-metal compounds containing structural metal dimers there may exist in the presence of different orbitals a special state with partial formation of singlets by electrons on one orbital, while others are effectively decoupled and may give, e. g., long-range magnetic order or stay paramagnetic. A similar situation can be realized in dimers spontaneously formed at structural phase transitions, which can be called the orbital-selective Peierls transition. This can occur in the case of strongly nonuniform hopping integrals for different orbitals and small intra-atomic Hund's rule coupling J(H). Yet another consequence of this picture is that for an odd number of electrons per dimer there exists competition between the double-exchange mechanism of ferromagnetism and the formation of a singlet dimer by the electron on one orbital, with the remaining electrons giving a net spin of a dimer. The first case is realized for strong Hund's rule coupling, typical for 3d compounds, whereas the second is more plausible for 4d-5d compounds. We discuss some implications of these phenomena, and consider examples of real systems, in which the orbital-selective phase seems to be realized.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Streltsov, Sergey V. UNSPECIFIED UNSPECIFIED UNSPECIFIED Khomskii, Daniel I. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-440536
DOI:	10.1103/PhysRevB.89.161112
Journal or Publication Title:	Phys. Rev. B
Volume:	89
Number:	16
Date:	2014
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	1550-235X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MAGNETIC-PROPERTIES; SPIN; LATTICE; V2O3; V4O7 Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/44053