Bilbao Crystallographic Server arrow k-Subgroupsmag Help

k-Subgroupsmag: Magnetic subgroups compatible with some given propagation vector(s) or a supercell.

The program k-Subgroupsmag provides the possible magnetic subgroups of the space group of a paramagnetic phase (gray group) which are possible for a magnetic ordering having a known propagation vector. The program provides the set of magnetic subgroups or a graph showing the subgroup-tree (grouped into conjugacy classes). In both cases, more information about the classes or subgroups can be obtained.

Other alternatives for the input of the program:

  • An alternative parent (non gray) magnetic group can be chosen.
  • Instead of the whole set of subgroups, the output can be limited to subgroups having a chosen common subgroup of lowest symmetry, common point group of lowest symmetry, or groups which belong to a specific crystal class.
  • Further restrictions on the subgroup list/graph considering physical properties can be used: it is possible to ask for only centrosymmetric or non-centrosymmetri groups, polar or non-polar groups.
  • More than one propagation wave-vector can be chosen.
  • The whole (or partial) stars of vectors can be introduced.
  • Non magnetic modulation wave-vectors can be also introduced.
  • Instead of propagation wave-vectors, a supercell can be given. In this case, all subgroups with their lattice defined by the supercell are given, including the gray ones.
  • It is possible to ask for a list/graph of subgroups compatible with the intermediate cells between the unit cell of the parent space group and the supercell determined by the given wave vector(s) (or the given supercell when the previous option is used).
  • The output can be further refined introducing the Wyckoff positions of the magnetic atoms (and the positions of the non-magnetic atoms for non-magnetic distortions) and/or a set of irreducible representations.

  • Tutorial: download

    You can find examples of application of this program in:

    Perez-Mato, JM; Gallego, SV; Elcoro, L; Tasci, E and Aroyo, MI
    J. of Phys.: Condens Matter (2016), 28:28601

    and in:

    J.M. Perez-Mato, S.V. Gallego, E.S. Tasci, L. Elcoro, G. de la Flor, and M.I. Aroyo
    Annu. Rev. Mater. Res. (2015), 45:13.1-13.32

    See the Help for details.

    Enter the generators of the Magnetic Space Group in the BNS setting, given in any basis of the lattice, as in the example:

     Assumed lattice translations:
     x + 1 , y , z, +1
     x , y + 1 , z, +1
     x , y , z + 1, +1

    Introduce the magnetic wave vector(s)
    (Give the components of the wave vectors in a fractional form, n/m)
    k1x    k1y    k1z 
    Choose the whole star of the propagation vector

    Include the subgroups compatible with intermediate cells.
    (It is not applied when only the maximal subgroups are calculated)

    Optional: possible limitations of the subgroup list
    (Check only one option on the left and the specific value on the right)
    Lowest space group to consider
    Lowest point group to consider
    Only subgroups with crystal system
    Only maximal subgroups

    Optional: further limitations considering physical properties of the point groups
  • Only centrosymmetric / non-centrosymmetric groups
  • Only polar / non-polar groups
  • List of subgroups Graph of subgroups

    Bilbao Crystallographic Server
    For comments, please mail to