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Ising phases of Heisenberg ladders in a magnetic field

Karlo Penc·Jean-Baptiste Fouet·Shin Miyahara·Oleg Tchernyshyov·Frederic Mila
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Abstract

We examine the influence of weak anisotropic interactions on the T=0 phase diagram of the frustrated two-leg Heisenberg ladder, a well-studied spin model exhibiting integer and fractional magnetization plateaux separated by gapless incommensurate states. We find that the Dzyaloshinskii--Moriya coupling may substantially modify the phase diagram so that the half-integer plateau and the surrounding gapless phases merge into a single Ising-ordered phase breaking the translational symmetry of the lattice. A different Ising order is found for a weakly frustrated ladder. Implications for experimental ladder and dimer systems are discussed.

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Karlo Penc, Jean-Baptiste Fouet, Shin Miyahara, Oleg Tchernyshyov, Frederic Mila. 2007-06-08. Ising phases of Heisenberg ladders in a magnetic field. https://doi.org/10.1103/physrevlett.99.117201

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