TY - JOUR

T1 - Theory of two-dimensional quantum Heisenberg antiferromagnets with a nearly critical ground state

AU - Chubukov, Andrey V.

AU - Sachdev, Subir

AU - Ye, Jinwu

PY - 1994

Y1 - 1994

N2 - We present the general theory of clean, two-dimensional, quantum Heisenberg antiferromagnets which are close to the zero-temperature quantum transition between ground states with and without long-range Néel order. While some of our discussion is more general, the bulk of our theory will be restricted to antiferromagnets in which the Néel order is described by a three-vector order parameter. For Néel-ordered states, nearly critical means that the ground-state spin stiffness, s, satisfies sJ, where J is the nearest-neighbor exchange constant, while nearly critical quantum-disordered ground states have an energy gap, , towards excitations with spin 1, which satisfies J. The allowed temperatures, T, are also smaller than J, but no restrictions are placed on the values of kBT/s or kBT/. Under these circumstances, we show that the wave vector and/or frequency-dependent uniform and staggered spin susceptibilities, and the specific heat, are completely universal functions of just three thermodynamic parameters. On the ordered side, these three parameters are s, the T=0 spin-wave velocity c, and the ground-state staggered moment N0; previous works have noted the universal dependence of the susceptibilities on these three parameters only in the more restricted regime of kBTs. On the disordered side the three thermodynamic parameters are , c, and the spin-1 quasiparticle residue scrA. Explicit results for the universal scaling functions are obtained by a 1/N expansion on the O(N) quantum nonlinear model, and by Monte Carlo simulations. These calculations lead to a variety of testable predictions for neutron scattering, NMR, and magnetization measurements. Our results are in good agreement with a number of numerical simulations and experiments on undoped and lightly doped La2-SrCuO4.

AB - We present the general theory of clean, two-dimensional, quantum Heisenberg antiferromagnets which are close to the zero-temperature quantum transition between ground states with and without long-range Néel order. While some of our discussion is more general, the bulk of our theory will be restricted to antiferromagnets in which the Néel order is described by a three-vector order parameter. For Néel-ordered states, nearly critical means that the ground-state spin stiffness, s, satisfies sJ, where J is the nearest-neighbor exchange constant, while nearly critical quantum-disordered ground states have an energy gap, , towards excitations with spin 1, which satisfies J. The allowed temperatures, T, are also smaller than J, but no restrictions are placed on the values of kBT/s or kBT/. Under these circumstances, we show that the wave vector and/or frequency-dependent uniform and staggered spin susceptibilities, and the specific heat, are completely universal functions of just three thermodynamic parameters. On the ordered side, these three parameters are s, the T=0 spin-wave velocity c, and the ground-state staggered moment N0; previous works have noted the universal dependence of the susceptibilities on these three parameters only in the more restricted regime of kBTs. On the disordered side the three thermodynamic parameters are , c, and the spin-1 quasiparticle residue scrA. Explicit results for the universal scaling functions are obtained by a 1/N expansion on the O(N) quantum nonlinear model, and by Monte Carlo simulations. These calculations lead to a variety of testable predictions for neutron scattering, NMR, and magnetization measurements. Our results are in good agreement with a number of numerical simulations and experiments on undoped and lightly doped La2-SrCuO4.

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U2 - 10.1103/PhysRevB.49.11919

DO - 10.1103/PhysRevB.49.11919

M3 - Article

AN - SCOPUS:30244458887

SN - 0163-1829

VL - 49

SP - 11919

EP - 11961

JO - Physical Review B

JF - Physical Review B

IS - 17

ER -