Dimer phase in the spin-1/2 frustrated chain

In this paper، the frustrated dimerized antiferromagnetic isotropic s=1/2 Heisenberg chain is studied. In this model، denotes the dimerization parameter for the exchange of nearest neighbors and denotes the frustration parameter for the exchange of next nearest neighbor interaction. Using the numerical Lanczos method، we have studied the magnetic phase diagram of the model in two subspaces. We have calculated the response functions of the system as a function of the frustrated parameter. According to the exact diagonalization results، by calculating order parameter، it is argued that، adding the dimerization will cause a phase transition between two different types of dimer phases.