On the incommensurate phase in modulated Heisenberg chains |
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Authors: | F Schönfeld G Bouzerar GS Uhrig E Müller-Hartmann |
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Institution: | Institut für Theoretische Physik, Universit?t zu K?ln, Zülpicher Strasse 77, K?ln 50937, Germany, DE
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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.
Received: 9 March 1998 / Accepted: 17 April 1998 |
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Keywords: | 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 |
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