Unconventional low dimensional fluctuation in organic conductors

有机导体非常规的低尺寸波动

基本信息

批准号：
09640429
负责人：
SUZUMURA Yoshikazu
金额：
$ 1.86万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

项目摘要

We have studied theoretically the following system based on the bosonization in order to study a role of correlation and fluctuation in low dimensional organic conductors. (i) The transition from insulator to metal occurs under pressures in the normal state of Bechgaard salts, which exhibit the charge gap. Such a transition is determined by a ratio of the charge gap to the interchain hopping. The mechanism has been studied by use of two-coupled chains with a half-filled band, in which the one-dimensional fluctuation is treated in terms of the renormalization group method. It is demonstrated that the confinement occurs when the charge gap becomes larger than than the interchain hopping. Further the effect of the electron-filling from the commensurate state has been examined. (2) The spin density wave of organic conductors exhibits a novel transition at temperature of the 1/3 of the critical temperature. By using a phase Hamiltonian for two-coupled chains of SDW, the effect of the phase difference between chain has been investigated by use of the transfer integral method. It is shown that the competition between the commensurability energy and interchain coupling gives rise to the transition from the commensurate state to the incommensurate state. (3) The effect of impurity in two-coupled spinless chain has been studied to understand the role of interchain hopping in quasi-one-dimensional systems. It is found that the one-dimensional localization occurs when the pinning energy of impurity becomes larger than the interaction induced interchain gap. Besides the above results, we have examined the electronic state of one-dimensional electrons, collective modes of spin density wave and the impurity effect on spin Peirls system.

从理论上讲，我们基于琼脂化研究了以下系统，以研究低维有机导体中相关性和波动的作用。（i）从绝缘体到金属的过渡发生在表现出电荷间隙的正常状态下的压力下。这种过渡取决于电荷差距与链跳的比率。通过使用两耦合链和半填充带来研究该机制，其中一维波动是根据重新规范化组方法来处理的。证明当电荷差距比链链跳跃大时，就会发生限制。进一步研究了来自相应状态的电子填充的效果。（2）有机导体的自旋密度波在临界温度的1/3温度下表现出新的过渡。通过使用SDW的两耦合链使用相位的hamiltonian，已经通过使用转移积分方法研究了链之间的相位差异的效果。结果表明，可辨能力和链链耦合之间的竞争引起了从相应状态到不一致状态的过渡。（3）已经研究了两耦合无旋转链中杂质的影响，以了解链跳跃在准二维系统中的作用。发现当杂质的固定能量大于相互作用引起的链间隙时，就会发生一维定位。除上述结果外，我们还研究了一维电子的电子状态，旋转密度波的集体模式以及对旋转Peirls系统的杂质效应。