TY - JOUR

T1 - The effect of quantum fluctuations on the ferromagnetic-helix transition in a Heisenberg tetragonal lattice with competing in-plane interactions

AU - Harris, A. B.

AU - Pimpinelli, Alberto

AU - Rastelli, E.

AU - Tassi, A.

PY - 1989/12/1

Y1 - 1989/12/1

N2 - Perturbative treatments of quantum fluctuations in Heisenberg helimagnets starting from the classical approximation fail because for S to infinity the spin wave is well defined only for a fixed helix wavevector Q. Recently an exact T-matrix evaluation of the contribution to the ground-state energy from long-wavelength quantum fluctuations near the classical ferromagnetic-helix (F-H) transition line was performed in order to discuss the zero-temperature phase diagram in the j2-J3 plane, where j2 (j3) sets the scale of second (third) neighbour interactions in the basal plane. For the hexagonal lattice it was shown that quantum fluctuations could change from second to first order the F-H transition near the F-AF-H classical triple point, where AF denotes antiferromagnet. Here the authors give analogous calculations on a tetragonal lattice, which show unexpected lattice-dependent features. In addition to a behaviour similar to that found on the hexagonal lattice near the F-AF-H triple point, the change of the order of transition is found also on a semi-infinite part of the classical F-H phase boundary.

AB - Perturbative treatments of quantum fluctuations in Heisenberg helimagnets starting from the classical approximation fail because for S to infinity the spin wave is well defined only for a fixed helix wavevector Q. Recently an exact T-matrix evaluation of the contribution to the ground-state energy from long-wavelength quantum fluctuations near the classical ferromagnetic-helix (F-H) transition line was performed in order to discuss the zero-temperature phase diagram in the j2-J3 plane, where j2 (j3) sets the scale of second (third) neighbour interactions in the basal plane. For the hexagonal lattice it was shown that quantum fluctuations could change from second to first order the F-H transition near the F-AF-H classical triple point, where AF denotes antiferromagnet. Here the authors give analogous calculations on a tetragonal lattice, which show unexpected lattice-dependent features. In addition to a behaviour similar to that found on the hexagonal lattice near the F-AF-H triple point, the change of the order of transition is found also on a semi-infinite part of the classical F-H phase boundary.

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U2 - 10.1088/0953-8984/1/24/005

DO - 10.1088/0953-8984/1/24/005

M3 - Article

AN - SCOPUS:36149037363

VL - 1

SP - 3821

EP - 3831

JO - Journal of Physics Condensed Matter

JF - Journal of Physics Condensed Matter

SN - 0953-8984

IS - 24

M1 - 005

ER -