Tensor-product state approach to spin-1/2 square J(1)-J(2) antiferromagnetic Heisenberg model: Evidence for deconfined quantum criticality
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AbstractThe 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.
All Author(s) ListLing Wang, Zheng-Cheng Gu, Frank Verstraete, Xiao-Gang Wen
Journal namePhysical Review B
Detailed descriptionArticle Number: 075143
Volume Number94
Issue Number7
LanguagesEnglish-United Kingdom
Web of Science Subject CategoriesPhysics, Condensed Matter;Physics

Last updated on 2020-18-10 at 02:05