Theoretical and Numerical Study on Anomalous Quantum Phenomena of the Spin Nanotube

点击翻译按钮获取中文摘要

As a starting point, we theoretically investigated the three-leg spin nanotube, which is the sinplest one. At first we studied the properties of the spin gap for the model in which the unit cell is a regular triangle, using the numerical exact diagonalization and the density matrix renormalization group (DMRG) method with the finite-size scaling. As a result, we found that the spin gap exists when the interchain interaction is antiferromagnetic, while gapless for ferromagnetic interaction. We also investigated some field-induced phenomena of the three-leg spin nanotube. Using the perturbation approximation about the saturation magnetization, we found that two new phases ; the field-induced chiral ordered phase and the inhomogeneous magnetization phase in the so-called Tomonaga-Luttinger liquid state.