Magnetism and Hund's rule in an optical lattice with cold fermions
Magnetism and Hund's rule in an optical lattice with cold fermions
We demonstrate that a two-dimensional (2D) optical lattice loaded with repulsive, contact-interacting fermions shows a rich and systematic magnetic phase diagram. Trapping a few (N ? 12) fermions in each of the single-site minima of the optical lattice, we find that the shell structure in these quantum wells determines the magnetism. In a shallow lattice, the tunnelling between the single wells is strong, and the lattice is non-magnetic (NM). For deeper lattices, however, the shell filling of the single wells with fermionic atoms determines the magnetism. As a consequence of Hund's first rule, the interaction energy is lowered by maximizing the number of atoms of the same species. This leads to a systematic sequence of NM, ferromagnetic (F) and antiferromagnetic (AF) phases.
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Kärkkäinen, K.
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Borgh, M.
a3c181f8-0535-46cd-bb9a-6e930a81f86e
Manninen, M.
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Reimann, S.M.
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21 February 2007
Kärkkäinen, K.
7285f0df-8b7a-4124-b995-69c9002ecd19
Borgh, M.
a3c181f8-0535-46cd-bb9a-6e930a81f86e
Manninen, M.
fd5106ea-6562-4c78-a65a-63f64c198fcb
Reimann, S.M.
5deb90dc-8734-4b9f-b760-93e99838cb81
Kärkkäinen, K., Borgh, M., Manninen, M. and Reimann, S.M.
(2007)
Magnetism and Hund's rule in an optical lattice with cold fermions.
New Journal of Physics, 9 (33), .
(doi:10.1088/1367-2630/9/2/033).
Abstract
We demonstrate that a two-dimensional (2D) optical lattice loaded with repulsive, contact-interacting fermions shows a rich and systematic magnetic phase diagram. Trapping a few (N ? 12) fermions in each of the single-site minima of the optical lattice, we find that the shell structure in these quantum wells determines the magnetism. In a shallow lattice, the tunnelling between the single wells is strong, and the lattice is non-magnetic (NM). For deeper lattices, however, the shell filling of the single wells with fermionic atoms determines the magnetism. As a consequence of Hund's first rule, the interaction energy is lowered by maximizing the number of atoms of the same species. This leads to a systematic sequence of NM, ferromagnetic (F) and antiferromagnetic (AF) phases.
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1367-2630_9_2_033.pdf
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Published date: 21 February 2007
Organisations:
Applied Mathematics
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Local EPrints ID: 198757
URI: http://eprints.soton.ac.uk/id/eprint/198757
PURE UUID: 48601f20-a108-4c42-8a74-8beff4bb88bd
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Date deposited: 06 Oct 2011 15:30
Last modified: 14 Mar 2024 04:14
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Author:
K. Kärkkäinen
Author:
M. Manninen
Author:
S.M. Reimann
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