## Abstract

A method is developed to make a Bose transformation which is restricted in proper space. A self-consistent independent spin wave representation (SCISWR) is found for two dimensional isotropic antiferromagnet of Heisenberg square lattices. In the SCISWR, we have successfully done the renormalization from both the dynamic and kinematic interaction and calculated the corrections from the correlations of the nearest neighbour and next nearest neighbour sites. An anisotropic excitation energy of spin wave in improper space is found self-consistently and has a gap. The difficulty of divergence appearing from higher order perturbation terms in the conventional spin wave theory has been overcome and the convergence in our approach seems quite good. We find the energy of ground state E approx. -0.659 in low order approximation and the magnetization of sublattice M{sup z} = 0.430 x (N/2) for system with spin 1/2. It is also proved that a physical spin excitation restricted in proper space is still isotropic and has no gap. (author). 17 refs.

## Citation Formats

Tao, Ruibao.
Improved spin wave theory: An application to the spin-1/2 antiferromagnetic Heisenberg model on a square lattice.
IAEA: N. p.,
1991.
Web.

Tao, Ruibao.
Improved spin wave theory: An application to the spin-1/2 antiferromagnetic Heisenberg model on a square lattice.
IAEA.

Tao, Ruibao.
1991.
"Improved spin wave theory: An application to the spin-1/2 antiferromagnetic Heisenberg model on a square lattice."
IAEA.

@misc{etde_10118564,

title = {Improved spin wave theory: An application to the spin-1/2 antiferromagnetic Heisenberg model on a square lattice}

author = {Tao, Ruibao}

abstractNote = {A method is developed to make a Bose transformation which is restricted in proper space. A self-consistent independent spin wave representation (SCISWR) is found for two dimensional isotropic antiferromagnet of Heisenberg square lattices. In the SCISWR, we have successfully done the renormalization from both the dynamic and kinematic interaction and calculated the corrections from the correlations of the nearest neighbour and next nearest neighbour sites. An anisotropic excitation energy of spin wave in improper space is found self-consistently and has a gap. The difficulty of divergence appearing from higher order perturbation terms in the conventional spin wave theory has been overcome and the convergence in our approach seems quite good. We find the energy of ground state E approx. -0.659 in low order approximation and the magnetization of sublattice M{sup z} = 0.430 x (N/2) for system with spin 1/2. It is also proved that a physical spin excitation restricted in proper space is still isotropic and has no gap. (author). 17 refs.}

place = {IAEA}

year = {1991}

month = {Sep}

}

title = {Improved spin wave theory: An application to the spin-1/2 antiferromagnetic Heisenberg model on a square lattice}

author = {Tao, Ruibao}

abstractNote = {A method is developed to make a Bose transformation which is restricted in proper space. A self-consistent independent spin wave representation (SCISWR) is found for two dimensional isotropic antiferromagnet of Heisenberg square lattices. In the SCISWR, we have successfully done the renormalization from both the dynamic and kinematic interaction and calculated the corrections from the correlations of the nearest neighbour and next nearest neighbour sites. An anisotropic excitation energy of spin wave in improper space is found self-consistently and has a gap. The difficulty of divergence appearing from higher order perturbation terms in the conventional spin wave theory has been overcome and the convergence in our approach seems quite good. We find the energy of ground state E approx. -0.659 in low order approximation and the magnetization of sublattice M{sup z} = 0.430 x (N/2) for system with spin 1/2. It is also proved that a physical spin excitation restricted in proper space is still isotropic and has no gap. (author). 17 refs.}

place = {IAEA}

year = {1991}

month = {Sep}

}