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Electronic and magnetic transitions in a multiband model for La2NiO4

Mahadevan, Priya and Sheshadri, K and Sarma, DD and Krishnamurthy, HR and Pandit, Rahul (1997) Electronic and magnetic transitions in a multiband model for La2NiO4. In: Physical Review B, 55 (15). pp. 9203-9206.


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The transition-metal oxide La2NiO4 is studied using a multiband Hubbard model with a Hund coupling J. We obtain its mean-field phase diagram in the U- (correlation strength on Ni sites) Delta (charge-transfer energy) plane. For J=0 we have a continuous transition from a paramagnetic metal (PMM) to a paramagnetic insulator (PMI). On increasing J, the magnetic moment M and the band gap EG change discontinuously at J=Jc(U, Delta ). For J=1, the insulating phase (AFI) is antiferromagnetic, but we have, in addition, both paramagnetic (PMM) and antiferromagnetic (AFM) metallic phases. The insulator-metal (AFI-AFM and AFI-PMM) phase boundaries are first order, but the metal-metal (AFM-PMM) boundary is second order; and it seems to meet the first-order boundary at a critical end point. A reentrant PMM-AFM-PMM sequence is also seen.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 10 Dec 2004
Last Modified: 19 Sep 2010 04:14
URI: http://eprints.iisc.ac.in/id/eprint/1125

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