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Crossover behavior of the J1-J2 model in a staggered magnetic field

H. Otsuka
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Abstract

The ground states of the $S=\frac12$ Heisenberg chain with the nearest-neighbor and the next-nearest-neighbor antiferromagnetic couplings are numerically investigated in a staggered magnetic field. While the staggered magnetic field may induce the Néel-type excitation gap, and it is characterized by the Gaussian fixed point in the spin-fluid region, the crossover to the behavior controlled by the Ising fixed point is expected to be observed for the spontaneously dimerized state at finite field. Treating a low-lying excitation gap by the phenomenological renormalization-group method, we numerically determine the massless flow connecting the Gaussian and Ising fixed points. Further, to check the criticalities, we perform the finite-size-scaling analysis of the excitation gap.

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H. Otsuka. 2003-01-17. Crossover behavior of the J1-J2 model in a staggered magnetic field. https://doi.org/10.1103/physrevb.66.172411

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