Reyes D, Continentino M A
Centro Brasileiro de Pesquisas Físicas-Rua Dr Xavier Sigaud, 150-Urca, 22290-180, RJ, Brazil.
J Phys Condens Matter. 2007 Oct 10;19(40):406203. doi: 10.1088/0953-8984/19/40/406203. Epub 2007 Sep 11.
Dimensional crossover in the Kondo necklace model is analyzed using the bond-operator method at zero and finite temperatures. Explicit relations describing quasi-two-dimensional properties are obtained by asymptotically solving the resulting equations. The crossover from two dimensions (2d) to three dimensions (3d) is investigated, turning on the electronic hopping ([Formula: see text]) of conduction electrons between different planes. In order to give continuity to our analysis, both cases of crossover, quasi-three-dimensional (q3d) and quasi-one-dimensional (q1d), are also investigated. The phase diagram as a function of temperature T, [Formula: see text] and [Formula: see text], where [Formula: see text] is the hopping within the planes, is calculated. Unusual reentrant behavior in the temperature-dependent antiferromagnetic critical line is found close to two dimensions. Near the isotropic three-dimensional quantum critical point the critical line is described by a standard power law with a square root dependence on the distance to the quantum critical point.
利用键算符方法在零温和有限温度下分析了近藤项链模型中的维度交叉。通过渐近求解所得方程，得到了描述准二维性质的显式关系。研究了从二维（2d）到三维（3d）的交叉，开启了不同平面间传导电子的电子跳跃（[公式：见原文]）。为了使我们的分析具有连续性，还研究了交叉的两种情况，即准三维（q3d）和准一维（q1d）。计算了作为温度T、[公式：见原文]和[公式：见原文]函数的相图，其中[公式：见原文]是平面内的跳跃。在接近二维时，发现了温度依赖反铁磁临界线中不寻常的重入行为。在各向同性三维量子临界点附近，临界线由标准幂律描述，对到量子临界点的距离有平方根依赖性。
