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Correlation driven metallic and half-metallic phases in a band insulator

Bag, S and Garg, A and Krishnamurthy, HR (2021) Correlation driven metallic and half-metallic phases in a band insulator. In: Physical Review B, 103 (15).

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Official URL: https://doi.org/10.1103/PhysRevB.103.155132


We demonstrate a mechanism for realizing ferrimagnetic metal, antiferromagnetic half-metal, and paramagnetic metal phases by tuning the onsite Coulomb repulsion U in a band insulator. In a simple model of a correlated band insulator, namely the ionic Hubbard model at half-filling, and in the presence of a second neighbor hopping, we show that as U is increased, first he insulating band gap is suppressed to zero at a critical U1 and remains zero within the paramagnetic metallic phase. Interestingly, at a larger Uc, ferrimagnetic order turns on, leading to a ferrimagnetic metallic phase for Uc<U<U2. For U>U2, the system exhibits an antiferromagnetic half-metallic phase, followed finally by a transition into an antiferromagnetic Mott insulator. Our results, based on dynamical mean-field theory, suggest alternate routes for achieving magnetically ordered metallic and half-metallic phases which have potential applications in spintronics. © 2021 American Physical Society.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Additional Information: The copyright for this article belongs to Authors
Keywords: Antiferromagnetism; Energy gap; Ferrimagnetism; Mean field theory; Mott insulators; Paramagnetism, Alternate routes; Antiferromagnetics; Band insulators; Coulomb repulsions; Dynamical mean-field theory; Ferrimagnetic order; Insulating bands; Ionic Hubbard model, Metals
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 11 Aug 2021 09:39
Last Modified: 11 Aug 2021 09:39
URI: http://eprints.iisc.ac.in/id/eprint/69098

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