3 papers
cond-mat.str-el1997
Elementary excitations in the gapped phase of a frustrated S=1/2 spin ladder: from spinons to the Haldane triplet
S. Brehmer, A. K. Kolezhuk, H. -J. Mikeska +1
We use the variational matrix-product ansatz to study elementary excitations in the S=1/2 ladder with additional diagonal coupling, equivalent to a single S=1/2 chain with alternat…
cond-mat1996
Spin ladders with nonmagnetic impurities
H. -J. Mikeska, U. Neugebauer, U. Schollwoeck
We investigate antiferromagnetic spin ladders with nonmagnetic impurities by variational and numerical (Lanczos and DMRG) methods. The interaction between the two unpaired spins op…
cond-mat1996
Phase diagram and hidden order for generalized spin ladders
S. Brehmer, H. -J. Mikeska, U. Neugebauer
We investigate the phase diagram of antiferromagnetic spin ladders with additional exchange interactions on diagonal bonds by variational and numerical methods. These generalized s…