Symmetries and Triplet Dispersion in a Modified Shastry-Sutherland Model for SrCu_2(BO_3)_2

Дата и время публикации : 2000-09-26T16:46:48Z

Авторы публикации и институты :
Christian Knetter
Erwin Mueller-Hartmann
Goetz S. Uhrig

Ссылка на журнал-издание: J.Phys.: Condens. Matter Vol 12 (Iss 42), 9069 (2000)
Коментарии к cтатье: 9 pages, 8 figures accepted by J. Phys.: Condens. Matter
Первичная категория: cond-mat.str-el

Все категории : cond-mat.str-el

Краткий обзор статьи: We investigate the one-triplet dispersion in a modified Shastry-Sutherland Model for SrCu_2(BO_3)_2 by means of a series expansion about the limit of strong dimerization. Our perturbative method is based on a continuous unitary transformation that maps the original Hamiltonian to an effective, energy quanta conserving block diagonal Hamiltonian H_{eff}. The dispersion splits into two branches which are nearly degenerated. We analyse the symmetries of the model and show that space group operations are necessary to explain the degeneracy of the dispersion at k=0 and at the border of the magnetic Brillouin zone. Moreover, we investigate the behaviour of the dispersion for small |k| and compare our results to INS data.

Category: Physics