The magnetic properties of spin-1/2 two-leg ladders with dimerized legs and trimerized modulation of rung exchange

The zero-temperature magnetic properties of spin-1/2 two-leg ladders with staggered and columnar dimerized legs and trimerized modulated rung exchange is studied using the numerical Lanczos method. A clear picture of the influence of different dimerizations on the appearance of magnetization plateaus is provided. It is found that the magnetization curve of the staggered ladders exhibits two plateaus at values 1/3Msat and 2/3Msat, and columnar ladders have an additional plateau at half of the saturation. The width of plateaus in staggered ladders is independent of dimerization on legs but in columnar ladders depends. The width of mid-plateau increases by enhancing the dimerized parameter on legs but others behave inversely. In addition, the effect of the dimerized parameter is studied on other functions as the energy gap, the on-rung spin-spin correlation and dimer order parameter.