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The European Physical Journal B
ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)
Abstract Volume 5 Issue 3 (1998) pp 521-528
On the incommensurate phase in modulated Heisenberg chains
F. Schönfeld (a), G. Bouzerar, G.S. Uhrig, E. Müller-Hartmann
Institut für Theoretische Physik, Universität zu Köln, Zülpicher Strasse 77, Köln 50937, Germany
Received: 9 March 1998 / Accepted: 17 April 1998
Abstract: Using the density matrix renormalization group method (DMRG) we calculate the magnetization of frustrated S=1/2 Heisenberg chains for various modulation patterns of the nearest neighbour coupling: commensurate, incommensurate with sinusoidal modulation and incommensurate with solitonic modulation. We focus on the order of the phase transition from the commensurate dimerized phase (D) to the incommensurate phase (I). It is shown that the order of the phase transition depends sensitively on the model. For the solitonic model in particular, a k-dependent elastic energy modifies the order of the transition. Furthermore, we calculate gaps in the incommensurate phase in adiabatic approximation.
PACS. 71.27.+a Strongly correlated electron systems; heavy fermions - 75.10.-b General theory and models of magnetic ordering - 75.10.Jm Quantized spin models
(a) email: fsch@thp.uni-koeln.de
Article in PDF format (358 KB)
Online publication: October 26, 1998
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