Quantum critical magnetization behaviors of kagome‐ and triangular‐lattice antiferromagnets

Our previous numerical diagonalization study on the magnetization processes of the kagome‐ and triangular‐lattice antiferromagnets revealed that the former system exhibits a new field‐induced phenomenon, called a magnetization ramp, at 1/3 of the saturation magnetization, while the latter one a conventional magnetization plateau. To clarify the difference between the magnetization ramp and plateau, we consider a generalized lattice model with two exchange interactions J 1 and J 2 , which corresponds to the kagome lattice for J 2  = 0 and triangular one for J 2  =  J 1 . The present numerical diagonalization study revealed that a quantum phase transition between the magnetization ramp and plateau occurs about J 2 / J 1  ∼ 0.1.