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Effective Field Theory for Layered Quantum Antiferromagnets with Non-Magnetic Impurities

Y. C. Chen·A. H. Castro Neto
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Abstract

We propose an effective two-dimensional quantum non-linear sigma model combined with classical percolation theory to study the magnetic properties of site diluted layered quantum antiferromagnets like La$_{2}$Cu$_{1-x}$M$_x$O$_{4}$ (M$=$Zn, Mg). We calculate the staggered magnetization at zero temperature, $M_s(x)$, the magnetic correlation length, $ξ(x,T)$, the NMR relaxation rate, $1/T_1(x,T)$, and the Néel temperature, $T_N(x)$, in the renormalized classical regime. Due to quantum fluctuations we find a quantum critical point (QCP) at $x_c \approx 0.305$ at lower doping than the two-dimensional percolation threshold $x_p \approx 0.41$. We compare our results with the available experimental data.

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Y. C. Chen, A. H. Castro Neto. 1999-12-06. Effective Field Theory for Layered Quantum Antiferromagnets with Non-Magnetic Impurities. https://doi.org/10.1103/physrevb.61.r3772

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