Quantum Spin Fluid Behaviors of the Kagome- and Triangular-Lattice Antiferromagnets

The S=1/2 kagome-lattice antiferromagnet is investigated using the numerical diagonalization of finite-size clusters. The analysis of the susceptibility at the zero magnetization indicateds that the magnetic excitation of the system is gapless. It is consistent with our previous finite-scaling analysis of the spin gap. The application of the method for the triangular-lattice antiferromagnet confirms the validity of the analysis