Magnetic state of the bulk, surface and nanoclusters of CaMnO sub(3: A DFT study)

The electronic structures of bulk, 2D slabs and clusters of CaMnO sub(3 in various magnetic configurations are presented. The obtained results including optimized cell constant, band-gap, Mn magnetic moment, on-site Coulomb repulsion potential and p-d charge separation potential are in good agreemen...

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Bibliographic Details
Published in:Physica. B, Condensed matter Condensed matter, 2011-10, Vol.406 (19), p.3613-3621
Main Authors: Nguyen, Thuy Trang, Bach, Thanh Cong, Pham, Huong Thao, Pham, The Tan, Nguyen, Duc Tho, Hoang, Nam Nhat
Format: Article
Language:English
Subjects:
Clusters
Condensed matter
Ground state
Manganese
Mathematical analysis
Nanostructure
Slabs
Two dimensional
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Summary:The electronic structures of bulk, 2D slabs and clusters of CaMnO sub(3 in various magnetic configurations are presented. The obtained results including optimized cell constant, band-gap, Mn magnetic moment, on-site Coulomb repulsion potential and p-d charge separation potential are in good agreement with experiment data. The energetically most preferable configuration was an insulating charge-transfer ground state with G-type antiferromagnetic (AF) configuration (classified according to Wollan and Koehler, Phys. Rev. 100 (1955) 545). For the finite 2D layers the C-type AF ground state was found to be most stable. The surface effect on magnetism of finite quasi 2D systems appeared to originate in the pyramidal field splitting of Mn 3d levels, which induced the formation of ferromagnetic (FM) regions within the AF matrix and the extension of FM correlation deep through 7 subsurface layers (2.7 nm from the surface). All finite systems (clusters and slabs) were found non-conducting due to the localization of electrons and the cancellation of surface excess carriers (holes) after surface relaxation, although the band-gaps of 2D systems were sufficiently reduced in comparison with that of the bulk.)
ISSN:0921-4526
DOI:10.1016/j.physb.2011.06.054