Ground state and thermodynamic properties of spin-1/2 isosceles Heisenberg triangles for V_{6}-like magnetic molecules

The spin-1/2 Hamiltonian for two coupled isosceles Heisenberg triangles, which is well suited for describing the V_{6}-type magnetic molecules, is studied by exact diagonalization. The quantum phase transition diagram, at zero temperature, is obtained as a function of the theoretical parameters. The zero temperature magnetization is also obtained as a function of the external magnetic field. The thermodynamic behavior of the magnetization, entropy, susceptibility, and specific heat, as a function of temperature, are also computed and the corresponding magnetocaloric effect analyzed for various values of the Hamiltonian parameters.