Ground state of an S = 1 / 2 distorted diamond chain — model of Cu 3 Cl 6 (H 2 O) 2 · 2H 8 C 4 SO 2
Ground state of an S = 1 / 2 distorted diamond chain — model of Cu 3 Cl 6 (H 2 O) 2 · 2H 8 C 4 SO 2
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发表时间：
1999
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通讯作者：
K. Okamoto;Taskashi Tonegawa;Yutaka Takahashi;M. Kaburagi
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作者：
K. Okamoto;Taskashi Tonegawa;Yutaka Takahashi;M. Kaburagi
.研究了S = 1/2的三聚量子Heisenberg链Cu3Cl6（H2O）2·2H8C4SO2的模型哈密顿量的基态，其中非磁性基态是最近观察到的.该模型由堆叠的三聚体组成，并且具有三种自旋之间的耦合常数：三聚体内耦合常数J1和三聚体间耦合常数J2和J3。所有这些常数都被假定为反铁磁的。利用分析方法和物理考虑，我们证明了在<$J2 − <$J3平面（<$J2 <$J2/J1，<$J3 <$J3/J1）上存在三种相：二聚物相、自旋半流体相和亚铁磁相.二聚体相是由阻挫效应引起的。在二聚物相中，在二重简并基态和第一激发态之间存在激发能隙，这解释了在Cu3Cl6（H2O）2·2H8C4SO2中观察到的非磁性基态.我们还利用Lanczos算法从有限系统的数值对角化数据中得到了π J2 − π J3平面上的相图。
. We study the ground state of the model Hamiltonian of the trimerized S = 1 / 2 quantum Heisenberg chain Cu 3 Cl 6 (H 2 O) 2 · 2H 8 C 4 SO 2 in which the non-magnetic ground state is observed recently. This model consists of stacked trimers and has three kinds of coupling constants between spins; the intra-trimer coupling constant J 1 and the inter-trimer coupling constants J 2 and J 3 . All of these constants are assumed to be antiferromagnetic. By use of the analytical method and physical considerations, we show that there are three phases on the ˜ J 2 − ˜ J 3 plane ( ˜ J 2 ≡ J 2 /J 1 , ˜ J 3 ≡ J 3 /J 1 ), the dimer phase, the spin fluid phase and the ferrimagnetic phase. The dimer phase is caused by the frustration effect. In the dimer phase, there exists the excitation gap between the two-fold degenerate ground state and the first excited state, which explains the non-magnetic ground state observed in Cu 3 Cl 6 (H 2 O) 2 · 2H 8 C 4 SO 2 . We also obtain the phase diagram on the ˜ J 2 − ˜ J 3 plane from the numerical diagonalization data for finite systems by use of the Lanczos algorithm.