https://doi.org/10.1007/s100510051052
Long-range spin-pairing order and spin defects in quantum spin-1/2 ladders
Departament de Física Fonamental, Facultat de
Física, Universitat de Barcelona, Diagonal 647,
08028 Barcelona, Catalunya, Spain
Received:
19
July
1999
Revised:
8
October
1999
Published online: 15 April 2000
For w-legged antiferromagnetic spin-1/2 Heisenberg ladders, a long-range spin pairing order can be identified which enables the separation of the space spanned by finite-range (covalent) valence-bond configurations into w+1 subspaces. Since every subspace has an equivalent counter subspace connected by translational symmetry, twofold degeneracy, breaking translational symmetry is found except for the subspace where the ground state of w = even belongs to. In terms of energy ordering, (non)degeneracy and the discontinuities introduced in the long-range spin pairing order by topological spin defects, the differences between even and odd ladders are explained in a general and systematic way.
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 75.10.Jm – Quantized spin models
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000
