TY - JOUR

T1 - Critical thermodynamics of cubic and tetragonal crystals with multicomponent order parameters

AU - Varnashev, K. B.

AU - Sokolov, A. I.

PY - 1996/12/1

Y1 - 1996/12/1

N2 - The critical behavior of a three-dimensional model describing antiferromagnetic and structural phase transitions in cubic and tetragonal crystals with 2N-component order parameters (N>1) is investigated in the two-loop approximation of renormalized perturbation theory. The derived re normalization group expansions are resummed by the Padé-Borel method, and it is established that a stable fixed point exists in the three-dimensional phase space of effective coupling constants, consistent with earlier predictions based on the ε-expansion. For the physically interesting cases N = 2 and N = 3, however, the critical exponents corresponding to this point are found to be numerically close, not to the exponents of O(2N)-symmetric systems, but to those of the three-dimensional XY model, which differ substantially from them. A comparative analysis of the results obtained by the ε-expansion technique and by the renormalization group method in three-dimensional space shows that the latter approach provides significantly higher accuracy in numerical estimates.

AB - The critical behavior of a three-dimensional model describing antiferromagnetic and structural phase transitions in cubic and tetragonal crystals with 2N-component order parameters (N>1) is investigated in the two-loop approximation of renormalized perturbation theory. The derived re normalization group expansions are resummed by the Padé-Borel method, and it is established that a stable fixed point exists in the three-dimensional phase space of effective coupling constants, consistent with earlier predictions based on the ε-expansion. For the physically interesting cases N = 2 and N = 3, however, the critical exponents corresponding to this point are found to be numerically close, not to the exponents of O(2N)-symmetric systems, but to those of the three-dimensional XY model, which differ substantially from them. A comparative analysis of the results obtained by the ε-expansion technique and by the renormalization group method in three-dimensional space shows that the latter approach provides significantly higher accuracy in numerical estimates.

UR - http://www.scopus.com/inward/record.url?scp=0030351833&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0030351833

VL - 38

SP - 1996

EP - 2002

JO - Physics of the Solid State

JF - Physics of the Solid State

SN - 1063-7834

IS - 12

ER -