Role of Phase Variables in Quarter-Filled Spin Density Wave States
Role of Phase Variables in Quarter-Filled Spin Density Wave States
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DOI：
10.1143/jpsj.69.796
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发表时间：
2000-03
影响因子：
1.7
通讯作者：
Y. Tomio;Y. Suzumura
中科院分区：
文献类型：
--
作者：
Y. Tomio;Y. Suzumura
本文重新研究了[小林等：J. Phys. Soc. Jpn.]中研究过的具有在位、最近邻和次最近邻排斥相互作用的一维系统中的几种既有四分之一填充带又有二聚化的自旋密度波（SDW）态。67（1998）1098]。在平均场理论中，基态和对密度变化的响应分别用相位变量θ和φ来计算，其中θ表示SDW的电荷涨落，φ分别描述上自旋密度波和下自旋密度波之间的相对运动.结果表明，2kF-SDW和2kF-电荷密度波（CDW）共存的奇异态之后是4kF-SDW，而不是4kF-CDW，其中kF表示费米波矢.在相互作用中，谐振势随θ和/或φ的变化消失，导致纯2kF-SDW态与相应的共存态之间的边界。
Several kinds of spin density wave (SDW) states with both quarter-filled band and dimerization are reexamined for a one-dimensional system with on-site, nearest-neighbor and next-nearest-neighbor repulsive interactions, which has been investigated by [Kobayashi et al. : J. Phys. Soc. Jpn. 67 (1998) 1098]. Within the mean-field theory, the ground state and the response to the density variation are calculated in terms of phase variables, θ and φ, where θ expresses the charge fluctuation of SDW and φ describes the relative motion between density wave with up spin and that with down spin respectively. It is shown that the exotic state of coexistence of 2 k F -SDW and 2 k F -charge density wave (CDW) is followed by 4 k F -SDW but not by 4 k F -CDW where k F denotes a Fermi wave vector. The harmonic potential with respect to the variation of θ and/or φ disappears for the interactions, which lead to the boundary between the pure 2 k F -SDW state and the corresponding coexistent state.