Phase diagram and critical properties of the frustrated Kondo necklace model in a magnetic field
The critical properties of the frustrated Kondo necklace model with a half saturation magnetization ($m=1/2$) have been studied by means of an exact-diagonalization method. It is shown from bosonization technique that the model can be effectively expressed as a quantum sine-Gordom model. Thus it may show three (dimer plateau, N{é}el plateau and Tomonaga-Luttinger liquid) phases due to competitions among the Ising anisotropy $Δ$, and the nearest- and next-nearest-neighbor exchange interactions $J_1$ and $J_2$. The boundary lines on the $Δ-J_2/J_1$ phase diagram separating the three phases are determined by the method of level spectroscopy based on the conformal field theory.
cond-mat.str-el↗