Communications in Physics 24
, 193-200 (2014)
MAGNETIC PROPERTIES OF QUANTUM SQUARE LATTICE HEISENBERG ANTIFERROMAGNET WITH FRUSTRATION: AN AUXILIARY FERMION APPROACH
PHAM THANH NGA, NGUYEN TOAN THANG
We study the magnetic ordered phases of the spin-1/2 Heisenberg antiferromagnetic model with nearest J1
and next nearest neighbor J2 exchange interactions on the square lattice using fermionic representation of spin operators
within Popov-Fedotov approach.The unphysical states are eliminated on each site by introducing an imaginary
chemical potential. Working in local coordinate system for every site we investigate the different ordered phases in
dependence on exchange parameters. At T = 0 we recover the conventional spin wave results.
Keywords: functional integral, antiferromagnetic Heisenberg model, square lattice, frustration.