Numerical Study of a Two-Dimensional Quantum Antiferromagnet with Random Ferromagnetic Bonds

Abstract

A Monte Carlo method for finite-temperature studies of the two-dimensional quantum Heisenberg antiferromagnet with random ferromagnetic bonds is presented. The scheme is based on an approximation which allows for an analytic summation over the realizations of the randomness, thereby significantly alleviating the ``sign problem'' for this frustrated spin system. The approximation is shown to be very accurate for ferromagnetic bond concentrations of up to ten percent. The effects of a low concentration of ferromagnetic bonds on the antiferromagnetism are discussed.

11 pages + 5 postscript figures (included), Revtex 3.0, UCSBTH-94-23

References in corpus (5)

• Gapless Spin-Fluid Ground State in a Random Quantum Heisenberg Magnet
• Universal quantum critical dynamics of two-dimensional antiferromagnets
• Zero--Temperature Quantum Phase Transition of a Two--Dimensional Ising Spin--Glass
• Universal Magnetic Properties of $L{a}_{2-\delta }S{r}_{\delta }Cu{O}_4$ at Intermediate Temperatures
• Random Exchange Disorder in the Spin-1/2 XXZ Chain

Cited by in corpus (4)

• Impurity effects at finite temperature in the two-dimensional S=1/2 Heisenberg antiferromagnet
• Thermodynamics of two-dimensional spin models with bimodal random-bond disorder
• Ground-State Phase Diagram of the Two-Dimensional Quantum Heisenberg Mattis Model
• Dynamical Critical Properties of the Random-Bond three-state Potts Model