UNIVERSALITY IN THE PARTIALLY ANISOTROPIC THREE-DIMENSIONAL ISING LATTICE
Yurishchev M.A.

Received: March 16, 2004

PACS: 05.50.+q, 05.70.Jk, 64.60.Fr, 75.10.Hk

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Using transfer-matrix extended phenomenological renormalization-group methods, we study the critical properties of the spin-1/2 Ising model on a simple-cubic lattice with partly anisotropic coupling strengths . The universality of both fundamental critical exponents y_t and y_h is confirmed. It is shown that the critical finite-size scaling amplitude ratios U=A_χ⁽⁴⁾A_κ/A_χ², Y₁=A_κ''/A_χ, and Y₂=A_κ⁽⁴⁾/A_χ⁽⁴⁾ are independent of the lattice anisotropy parameter Δ=J'/J. For the Y₂ invariant of the three-dimensional Ising universality class, we give the first quantitative estimate (shape , periodic boundary conditions in both transverse directions).