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Magnetism and Hund's rule in an optical lattice with cold fermions

Kärkkäinen, Kimmo LU ; Borgh, Magnus LU ; Manninen, M. and Reimann, Stephanie LU (2007) In New Journal of Physics 9.
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,... (More)
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. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
New Journal of Physics
volume
9
publisher
IOP Publishing Ltd.
external identifiers
  • wos:000244400400001
  • scopus:33847234283
ISSN
1367-2630
DOI
10.1088/1367-2630/9/2/033
language
English
LU publication?
yes
id
98a4f9d7-1e72-4b76-91b8-7281bf1ad21e (old id 674484)
date added to LUP
2007-12-13 16:17:05
date last changed
2017-01-01 06:59:34
@article{98a4f9d7-1e72-4b76-91b8-7281bf1ad21e,
  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 &lt;= 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.},
  articleno    = {33},
  author       = {Kärkkäinen, Kimmo and Borgh, Magnus and Manninen, M. and Reimann, Stephanie},
  issn         = {1367-2630},
  language     = {eng},
  publisher    = {IOP Publishing Ltd.},
  series       = {New Journal of Physics},
  title        = {Magnetism and Hund's rule in an optical lattice with cold fermions},
  url          = {http://dx.doi.org/10.1088/1367-2630/9/2/033},
  volume       = {9},
  year         = {2007},
}