Disproportionation and electronic phase separation in parent manganite LaMnO3 / Moskvin A. S. // PHYSICAL REVIEW B. - 2009. - V. 79, l. 11.

ISSN/EISSN:

2469-9950 / 2469-9969

Type:

Article

Abstract:

Nominally pure undoped parent manganite LaMnO3 exhibits a puzzling behavior inconsistent with a simple picture of an A-type antiferromagnetic insulator (A-AFI) with a cooperative Jahn-Teller ordering. We do assign its anomalous properties to charge transfer (CT) instabilities and competition between insulating A-AFI phase and metalliclike dynamically disproportionated phase formally separated by a first-order phase transition at T-disp=T-JT approximate to 750 K. The unconventional high-temperature phase is addressed to be a specific electron-hole (EH) Bose liquid (EHBL) rather than a simple ``chemically{''} disproportionated La(Mn2+Mn4+)O-3 phase. The phase does nucleate as a result of the CT instability and evolves from the self-trapped CT excitons or specific EH dimers, which seem to be a precursor of both insulating and metalliclike ferromagnetic phases observed in manganites. We arrive at highly frustrated system of triplet (e(g)(2))(3)A(2g) bosons moving in a lattice formed by hole Mn4+ centers. Starting with different experimental data we have reproduced a typical temperature dependence of the volume fraction of high-temperature mixed-valence EHBL phase. We argue that a slight nonisovalent substitution, photoirradiation, external pressure, or magnetic field gives rise to an electronic phase separation with a nucleation or an overgrowth of EH droplets. Such a scenario provides a comprehensive explanation of numerous puzzling properties observed in parent and nonisovalently doped manganite LaMnO3 including an intriguing manifestation of superconducting fluctuations.

Author keywords:

antiferromagnetic materials; charge exchange; chemical exchanges; excitons; insulating materials; Jahn-Teller effect; lanthanum compounds; mixed valence compounds; phase separation X-RAY-ABSORPTION; MIXED-VALENCE MANGANITES; MN K-EDGE; MAGNETIC-PROPERTIES; THERMOELECTRIC-POWER; NEUTRON-DIFFRACTION; HIGH-TEMPERATURE; MAGNETORESISTIVE MANGANITES; LANTHANUM MANGANITES; CRYSTAL-STRUCTURE

DOI:

10.1103/PhysRevB.79.115102

Web of Science ID:

ISI:000264768900029

Соавторы в МНС:

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Другие поля

Поле	Значение
Month	MAR
Publisher	AMER PHYSICAL SOC
Address	ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Language	English
Article-Number	115102
EISSN	2469-9969
Keywords-Plus	X-RAY-ABSORPTION; MIXED-VALENCE MANGANITES; MN K-EDGE; MAGNETIC-PROPERTIES; THERMOELECTRIC-POWER; NEUTRON-DIFFRACTION; HIGH-TEMPERATURE; MAGNETORESISTIVE MANGANITES; LANTHANUM MANGANITES; CRYSTAL-STRUCTURE
Research-Areas	Physics
Web-of-Science-Categories	Physics, Condensed Matter
Funding-Acknowledgement	RFBR {[}06-02-17242, 07-02-96047, 08-02-00633]
Funding-Text	I thank N. N. Loshkareva, Yu. P. Sukhorukov, K. N. Mikhalev, Yu. B. Kudasov, and V. V. Platonov for stimulating and helpful discussions. The work was supported by RFBR under Grants No. 06-02-17242, No. 07-02-96047, and No. 08-02-00633.
Number-of-Cited-References	101
Usage-Count-Last-180-days	2
Usage-Count-Since-2013	19
Journal-ISO	Phys. Rev. B
Doc-Delivery-Number	427GX