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Critical spin dynamics of the 2D quantum Heisenberg antiferromagnets: Sr_2CuO_2Cl_2 and Sr_2Cu_3O_4Cl_2

Y. J. Kim·R. J. Birgeneau·F. C. Chou·R. W. Erwin·M. A. Kastner
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Abstract

We report a neutron scattering study of the long-wavelength dynamic spin correlations in the model two-dimensional $S=1/2$ square lattice Heisenberg antiferromagnets Sr$_2$CuO$_2$Cl$_2$ and Sr$_2$Cu$_3$O$_4$Cl$_2$. The characteristic energy scale, $ω_0 (T/J)$, is determined by measuring the quasielastic peak width in the paramagnetic phase over a wide range of temperature ($0.2 \alt T/J \alt 0.7$). The obtained values for $ω_0 (T/J)$ agree {\it quantitatively} between the two compounds and also with values deduced from quantum Monte Carlo simulations. The combined data show scaling behavior, $ω\sim ξ^{-z}$, over the entire temperature range with $z=1.0(1)$, in agreement with dynamic scaling theory.

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Y. J. Kim, R. J. Birgeneau, F. C. Chou, R. W. Erwin, M. A. Kastner. 2001-02-13. Critical spin dynamics of the 2D quantum Heisenberg antiferromagnets: Sr_2CuO_2Cl_2 and Sr_2Cu_3O_4Cl_2. https://doi.org/10.1103/physrevlett.86.3144

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