scholarly journals Exact diagonalization study of the antiferromagnetic spin-12Heisenberg model on the square lattice in a magnetic field

2009 ◽  
Vol 79 (19) ◽  
Author(s):  
Andreas Lüscher ◽  
Andreas M. Läuchli
Keyword(s):  
Magnetic Field ◽  
Exact Diagonalization ◽  
Square Lattice ◽  
Antiferromagnetic Spin

Effects of a magnetic field in Kondo insulators: An exact diagonalization study of the Anderson lattice model

1997 ◽  
Vol 230-232 ◽  
pp. 421-424 ◽  
Author(s):  
K. Tsutsui ◽  
Y. Ohta ◽  
R. Eder ◽  
S. Maekawa ◽  
E. Dagotto ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Lattice Model ◽  
Exact Diagonalization ◽  
Kondo Insulators

THE SIMULATION OF 2D SPIN-1 ISING MODEL WITH POSITIVE BIQUADRATIC INTERACTION ON A CELLULAR AUTOMATON

2003 ◽  
Vol 14 (10) ◽  
pp. 1305-1320 ◽  
Author(s):  
BÜLENT KUTLU
Keyword(s):  
Phase Transition ◽  
Ising Model ◽  
Cellular Automaton ◽  
Intermediate Phase ◽  
Finite Size ◽  
Square Lattice ◽  
Two Dimensional ◽  
Finite Size Scaling ◽  
Creutz Cellular Automaton ◽  
Antiferromagnetic Spin

The two-dimensional antiferromagnetic spin-1 Ising model with positive biquadratic interaction is simulated on a cellular automaton which based on the Creutz cellular automaton for square lattice. Phase diagrams characterizing phase transition of the model are presented for a comparison with those obtained from other calculations. We confirm the existence of the intermediate phase observed in previous works for some values of J/K and D/K. The values of the static critical exponents (β, γ and ν) are estimated within the framework of the finite-size scaling theory for D/K<2J/K. Although the results are compatible with the universal Ising critical behavior in the region of D/K<2J/K-4, the model does not exhibit any universal behavior in the interval 2J/K-4<D/K<2J/K.

Thermodynamic Properties of an In-Phase Flux Antiferromagnetic Spin Coupled Heisenberg Model on a Square Lattice

SPIN ◽  
2018 ◽  
Vol 08 (04) ◽  
pp. 1830001
Author(s):  
E. Mainimo ◽  
N. Ibrahim Famenyi
Keyword(s):  
Energy Spectrum ◽  
Specific Heat ◽  
Thermodynamic Parameters ◽  
Heisenberg Model ◽  
State Energy ◽  
Spontaneous Magnetization ◽  
Exchange Interactions ◽  
Spin Model ◽  
Square Lattice ◽  
Antiferromagnetic Spin

Using the two-dimensional Jordan–Wigner Fermionization procedure, we calculate the energy spectrum of the in-phase flux antiferromagnetically spin-1/2 coupled Heisenberg model in a square lattice, the formalism used introduces the notion of isotropic parameters. The energy spectrum is analyzed for various regimes of the exchange interactions and the isotropic parameters. The thermodynamic parameters of the lattice, notably the ground state energy, the free energy, mean energy, entropy and specific heat are calculated. It is seen that the specific heat undergoes a phase transition at a temperature below the critical temperature due to spontaneous magnetization. Its entropy for homogeneous and completely isotropic regime is compared for two regimes of the exchange interaction and it is observed that the entropy decreases with an increase in the coupling strength. All the thermodynamic parameters calculated for this spin model are seen to be in conformity with the principles and laws of Statistical Thermodynamics.

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