We determine the one-particle spectral function and the corresponding derived quantities for the conducting chain lattice with the finite inter-chain hopping $t_\perp$ and the three-dimensional long-range Coulomb electron-electron interaction. The standard $G_{0}W_{0}$ approximation is used. It is shown that, due to the optical character of the anisotropic plasmon dispersion caused by the finite $t_\perp$, the low energy quasi-particle $δ$-peak appears in the spectral function in addition to the hump present at the energies of the order of plasmon energy. The particular attention is devoted to the continuous cross-over from the non-Fermi liquid to the Fermi liquid regime by increasing $t_\perp$. It is shown that the spectral weight of the hump transfers to the quasi-particle as the optical gap in the plasmon dispersion increases together with $t_\perp$, with the quasi-particle residuum $Z$ behaving like $- (\ln t_{\perp})^{-1}$ in the limit $t_{\perp}\to 0$. Our approach is appropriate for the wide range of energy scales given by the plasmon energy and the width of the conduction band, and is complementary to the Luttinger liquid techniques that are limited to the low energy regime close to the Fermi surface.
Role of Interlayer Electron Hopping for Spin Density Wave State in the Zero-Gap Organic Conductor
研究了准二维有机导体$α$ -(BEDT-TTF)$_2$ I $_3$盐在静水压力下零能隙态(ZGS)密度波的形成. ZGS的导带和价带在二维波矢处都呈现锥形色散,相互简并,$\pm\mib{k}_0$形成零带隙。通过使用扩展的哈伯德模型与排斥相互作用,我们计算的自旋密度波(SDW)的起始温度作为层间电子跳跃的函数,这本身并不打破锥状色散。结果表明,波数为$2\mib{k}_0$的SDW是由相互作用、带间激发和层间跃迁共同作用的结果。
Possible co-existence of local itinerancy and global localization in a quasi-one-dimensional conductor
在链状化合物PrBa $_2$ Cu $_4$ O $_8$中,当链中的散射速率超过链间的跳跃速率时,局域化与电子基态中的空间交叉同时出现.在这里,我们报告了一个大的发现,横向磁阻PrBa $_2$ Cu $_4$ O $_8$在本地化制度。这一结果表明,一种新的形式的本地化,使电子保留其金属(准一维)字符在微观长度尺度上,尽管事实上,宏观上,他们表现出本地化(一维)的行为。
Low-q dispersion of transverse acoustic phonons in YBa$_2$Cu$_3$O$_{7-δ}$
高分辨率($ΔE$ =1.3毫电子伏)的非弹性X射线散射(IXS)在最佳掺杂的非孪晶YBa $_2$铜$_3$ O $_{7-δ}$单晶表明,横向声学声子在a方向的色散保持线性,没有软化,由于在长波长极限的弯曲模式,下降到q=0.02。声速为2700 +/- 70 m s $^{-1}$,与超声测量结果非常一致,并且从室温冷却到98 K时不变。这些结果排除了强烈的耦合之间的弯曲动力学的CuO $_2$平面和载流子在铜酸盐。
Excitations in the quantum paramagnetic phase of the quasi-one-dimensional Ising magnet CoNb$_2$O$_6$ in a transverse field: Geometric frustration and quantum renormalization effects
准一维Ising铁磁体CoNb $_2$ O $_6$在外加横向磁场的作用下发生了从自发磁序到量子顺磁序的连续量子相变,观察到自旋动力学的显著变化,表现出弱微扰的一维Ising量子临界特性.我们在这里报告广泛的单晶非弹性中子散射测量的磁激发在整个三维(3D)布里渊区的量子顺磁相刚好在临界场以上的有限链间耦合的影响进行表征。在这个阶段,我们观察到,激发有一个尖锐的,分辨率有限的线形在低能量和大部分的色散带宽,自旋翻转准粒子的预期。我们沿着强色散链方向映射的全带宽,并解决明确调制的色散在垂直于链的平面中,在反铁磁等腰三角形晶格中的链间耦合的特性受挫。分散体可以很好地参数化使用线性自旋波模型,包括链间耦合和进一步的邻居交换。沿链方向观察到的色散带宽小于线性自旋波模型使用在零场确定的交换值所预测的,这种效应归因于量子重整化的色散超出自旋波近似在略高于临界场的领域,量子波动仍然显着。