Novel field-induced quantum phase transition of the kagome-lattice antiferromagnet

Sakai, Toru; Nakano, Hiroki*

The kagome-lattice antiferromagnet is investigated using the numerical exact diagonalization up to 42-spin clusters. From our investigation of the magnetization process, we found a novel field-induced quantum phase transition, called the "magnetization ramp", at 1/3 of the saturation magnetization. The finite-size scaling analysis of the critical exponents indicated a significant difference of the magnetization ramp from the magnetization plateau observed in the triangular-lattice antiferromagnet.