(color online) The specific heat coefficients C/T vs temperature T for λ = h_x/J = 1, D_z = −0.4J, D_x = 1.0J, and N = 2000, (a) within the temperature window T ∈ [0, 4]; (b) for the impurity strength x = J_imp/J = 0.6, 0.9, 1.0, and 1.5 within the low temperature range of [0, 0.2]; (c) for the systems with S = 1/2 impurity (the light blue dashed line) and S = 1 impurity (the solid red line), and for the pure S = 1/2 Ising system (the dark blue dashed line), where x = 1.