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Frustrated ferromagnetic spin-1/2 chain in a magnetic field: The phase diagram and thermodynamic properties

F. Heidrich-Meisner·A. Honecker·T. Vekua
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Abstract

The frustrated ferromagnetic spin-1/2 Heisenberg chain is studied by means of a low-energy field theory as well as the density-matrix renormalization group and exact diagonalization methods. Firstly, we study the ground-state phase diagram in a magnetic field and find an `even-odd' (EO) phase characterized by bound pairs of magnons in the region of two weakly coupled antiferromagnetic chains. A jump in the magnetization curves signals a first-order transition at the boundary of the EO phase, but otherwise the curves are smooth. Secondly, we discuss thermodynamic properties at zero field, where we confirm a double-peak structure in the specific heat for moderate frustrating next-nearest neighbor interactions.

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F. Heidrich-Meisner, A. Honecker, T. Vekua. 2006-09-05. Frustrated ferromagnetic spin-1/2 chain in a magnetic field: The phase diagram and thermodynamic properties. https://doi.org/10.1103/physrevb.74.020403

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