Quantum critical phenomena in magnetization process of the Kagome and triangular lattice antiferromagnets
Tôru Sakai, Hiroki Nakano
Using the numerical exact diagonalization of finite-size clusters up to 39 spins, we investigate the magnetization process of the Kagome lattice antiferromagnet, as well as the triangular lattice antiferromagnet. A finite-size scaling analysis at 1/3 of the saturation magnetization indicates that an unconventional quantum phase transition, so called a magnetization ramp, occurs for the Kagome lattice antiferromagnet. In contrast, the triangular lattice antiferromagnet is revealed to exhibit a conventional 1/3 magnetization plateau. These conclusions are based on the estimated critical exponet δ defined as | m – m c | ∼ | H – H c | 1/ δ . The exponents at the lower and higher field sides of m = 1/3 δ − and δ + are estimated as δ − = 1.9 ± 1.0 and δ + = 0.5 ± 0.2 for the Kagome kattice, while δ − = 1.0 ± 0.2 and δ + = 0.8 ± 0.2 for the triangular lattice.
Journal of Physics Conference Series•Sep 28, 2011•4 citations