2000/10/19 by A. Sherman, Michael Schreiber, M. Schreiber · 1 citation
Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Condensed matter physics #Energy (signal processing) #Ferromagnetism #Heisenberg model #Ising model #Magnetic properties of thin films #Mathematical physics #Mathematics #Monte Carlo method #Physics #Physics of Superconductivity and Magnetism #Quantum Monte Carlo #Quantum mechanics #Spin (aerodynamics) #Spin wave #Square lattice #Thermodynamics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.63.214421
15 pages, 6 ps figures
arxiv created 2000/10/19 · openalex publication_date 2001/05/14 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We use the diagram technique for spin operators to calculate Green's functions and observables of the spin-(1)/(2) quantum Heisenberg antiferromagnet on a square lattice. The first corrections to the self-energy and interaction are taken into account in the chain diagrams. The approximation reproduces main results of Takahashi's modified spin-wave theory [Phys. Rev. B 40, 2494 (1989)] and is applicable in a wider temperature range. The energy per spin calculated in this approximation is in good agreement with the Monte Carlo and small-cluster exact-diagonalization calculations in the range 0<~T\ensuremath\lesssim1.2J where J is the exchange constant. For the static uniform susceptibility the agreement is good for T\ensuremath\lesssim0.6J and becomes somewhat worse for higher temperatures. Nevertheless the approximation is able to reproduce the maximum in the temperature dependence of the susceptibility near T=0.9J.