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arXiv · 2012.11853

The non-analytic momentum dependence of spin susceptibility of Heisenberg magnets in paramagnetic phase and its effect on critical exponents

A. A. Katanin
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Abstract

We study momentum dependence of static magnetic susceptibility $χ(q)$ in paramagnetic phase of Heisenberg magnets and its relation to critical behavior within nonlinear sigma model (NLSM) at arbitrary dimension $2 5/2$. Using NLSM, we obtain the contribution of the"anomalous" term $ξ^{-2}f(qξ)$ to the critical exponent $ν$, comparing it to the contribution of the non-analytical dependence, originating from the critical exponent $η$ (the obtained critical exponents $ν$ and $η$ agree with previous studies). In the range $3\leq d<4$ we find that the former contribution dominates, and fully determines $1/N$ correction to the critical exponent $ν$ in the limit $d\rightarrow 4.$

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A. A. Katanin. 2021-01-03. The non-analytic momentum dependence of spin susceptibility of Heisenberg magnets in paramagnetic phase and its effect on critical exponents. https://doi.org/10.1103/physrevb.103.054415

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