Tensor-product state approach to spin-1-2 square J₁-J₂ antiferromagnetic Heisenberg model: evidence for deconfined quantum criticalityReport as inadecuate




Tensor-product state approach to spin-1-2 square J₁-J₂ antiferromagnetic Heisenberg model: evidence for deconfined quantum criticality - Download this document for free, or read online. Document in PDF available to download.

(2016)PHYSICAL REVIEW B.94(7). Mark abstract The ground state phase of a spin-1/2 J(1)-J(2) antiferromagnetic Heisenberg model on a square lattice around the maximally frustrated regime (J(2) similar to 0.5J(1)) has been debated for decades. Here we study this model using the cluster update algorithm for tensor-product states (TPSs). The ground state energies at finite sizes and in the thermodynamic limit (with finite size scaling) are in good agreement with exact diagonalization study. Through finite size scaling of the spin correlation function, we find the critical point J(2)(c1) = 0.572(5) J(1) and critical exponents nu = 0.50(8), eta(s) = 0.28(6). In the range of 0.572 < J(2)/J(1) <= 0.6 we find a paramagnetic ground state with an exponentially decaying spin-spin correlation. Up to a 24x24 system size, we observe power law decaying dimer-dimer and plaquette-plaquette correlations with an anomalous plaquette scaling exponent eta(p) = 0.24(1) and an anomalous columnar scaling exponent eta(c) = 0.28(1) at J(2)/J(1) = 0.6. These results are consistent with a potential gapless U(1) spin-liquid phase. However, since the U(1) spin liquid is unstable due to the instanton effect, a valence bond solid order with very small amplitude might develop in the thermodynamic limit. Thus, our numerical results strongly indicate a deconfined quantum critical point at J(2)(c1). Remarkably, all the observed critical exponents are consistent with the J-Q model.

Please use this url to cite or link to this publication: http://hdl.handle.net/1854/LU-8152466



Author: Ling Wang, Zheng-Cheng Gu, Frank Verstraete and Xiao-Gang Wen

Source: https://biblio.ugent.be/publication/8152466



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