Communications in Physics 29, 119-128 (2019)

ISSN: 0868-3166

MAGNETIC ORDER IN HEISENBERG MODELS ON NON-BRAVAIS LATTICE: POPOV-FEDOTOV FUNCTIONAL METHOD

PHAM THI THANH NGA, NGUYEN TOAN THANG

We study magnetic properties of ordered phases in the Heisenberg model on a non- Bravais lattice by means of a Popov - Fedotov trick, which takes into account a rigorous constraint of a single occupancy. We derive the magnetization and the free energy using sadle point approximation in the functional integral formalism. We illustrate the application of the Popov – Fedotov approach to the Heisenberg antiferromagnet on a honeycomb lattice.

DOI: 10.15625/0868-3166/29/2/13508

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