Open AccessFermionized Heisenberg model on a non-Bravais lattice with exact local constraint: Application to a honeycomb lattice
Author(s) -
Phạm Thu Nga,
Nguyen Toan Thang
Publication year - 2019
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1274/1/012012
Subject(s) - bravais lattice , heisenberg model , lattice (music) , boson , physics , ground state , mathematical physics , quantum mechanics , mathematics , ferromagnetism , crystal structure , chemistry , acoustics , crystallography
We study magnetic order of the Heisenberg model on a non-Bravais lattice based on the Popov - Fedotov trick for exactly treating the local constraint on on-site spin number. The spin operators are represented by auxiliary fermions and an imaginary chemical potential is introduced. The following steps are sketched: i) Parameterizing classical ground state by a magnetic ordering vector and angles between the spins within a unit cell. ii) Going to a local coordinate system. ii) Using functional integral representation with Hubbard-Stratonovich for partition function and calculating determinants of block matrices by Silvester-Powel method. For illustration we obtain some explicit expressions for ferromagnetic Heisenberg model on a honeycomb lattice and compare them with the slave boson results.