Optical properties of one- and two-dimensional Hubbard and t-J models.
Optical properties of one- and two-dimensional Hubbard and t-J models.
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DOI：
10.1103/physrevb.42.8736
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发表时间：
1990-11
期刊：
影响因子：
--
通讯作者：
Stéphan;Horsch
中科院分区：
文献类型：
--
作者：
Stéphan;Horsch
用Lanczos算法数值计算了Hubbard模型和t-J模型的光学电导率。对于t-J模型和Hubbard模型系统，研究了具有周期和开放边界条件的一维和二维系统，包括多达16个站点和多达9个站点的系统。在一维情况下，即使对于t量级的J，远离半填充的电导率的低频部分也几乎完全由单一的数学函数(德鲁德峰)组成，这是电荷和自旋在一维上解耦的直接结果。在两个维度上，在德鲁德峰上方有一个额外的宽吸收带，这与实验观察到的铜氧化物超导体的中红外带一致。通过比较精确的电导率和精确的单粒子格林函数的卷积积分，证明了顶点修正的重要性。
The optical conductivity for the Hubbard and t-J models is calculated numerically by use of a Lanczos algorithm. One- and two-dimensional systems of up to 16 sites with periodic and open boundary conditions are examined for the t-J model, as well as Hubbard-model systems of up to 9 sites. In the one-dimensional case, the low-frequency part of the conductivity away from half filling is shown to consist almost entirely of a single \ensuremath{\delta} function (Drude peak) even for J of the order of t. This is a direct consequence of the decoupling of charge and spin in one dimension. In two dimensions there is an additional broad absorption band above the Drude peak, consistent with the experimentally observed midinfrared band in the copper oxide superconductors. The importance of vertex corrections is demonstrated by comparing the exact conductivity with the convolution integral of the exact single-particle Green's function.