Superconductivity in Organic Compounds with Pseudo-Triangular Lattice
Superconductivity in Organic Compounds with Pseudo-Triangular Lattice
复制标题
具有伪三角形晶格的有机化合物的超导性
DOI：
10.1143/jpsj.73.812
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发表时间：
2004
影响因子：
1.7
通讯作者：
T. Moriya
中科院分区：
文献类型：
--
作者：
H. Kondo;T. Moriya
研究了半填充正方晶格Hubbard模型中自旋涨落（SF）介导的超导电性（SC），考虑了该模型在有机κ-（BEDT-TTF）2X化合物中的应用.将t '/ t值从0变化到1，可以在正方形和等边三角形晶格之间进行插值，后者对反铁磁（AF）耦合自旋系统产生阻挫。在波动交换近似下，我们计算了不同模型参数值下的χ（q，ω），Tc和SC序参量，发现AF和SC都随着接近挫折几何而被抑制，|（t '/ t）-1| →0。然而，对于实际的U / t值，SC相位延伸超出AF相位边界，相当接近t '/ t = 1。对于t '/t1，序参量为x2-y2型.
We study spin fluctuation (SF) mediated superconductivity (SC) in a half-filled square lattice Hubbard model with the transfer matrices - t between nearest neighbor sites and - t ' between a half of next nearest neighbor sites neighboring along only one of the directions, considering application of this model to organic κ-(BEDT-TTF) 2 X compounds. Varying the t '/ t value from 0 to 1, one can interpolate between a square and an equilateral triangular lattice, the latter giving frustration to antiferromagnetically (AF) coupled spin systems. Within the fluctuation exchange (FLEX) approximation, we calculate χ( q ,ω), T c and the SC order parameter for various model parameter values and find that both AF and SC are suppressed as one approaches the frustration geometry or |( t '/ t )-1| →0. The SC phase, however, extends beyond the AF phase boundary fairly close to t '/ t = 1 for realistic U / t values. The order parameter is of x 2 - y 2 -type for t '/ t 1.