Dynamical Mean Field Study of the Kondo Lattice Model with Frustration-猫眼课题宝

受挫近藤晶格模型的动态平均场研究

DOI：

10.1088/1742-6596/320/1/012057

发表时间：

2011

期刊：

Journal of Physics : Conference Series

影响因子：

通讯作者：

中科院分区：

文献类型：

作者：

R.Peters;N.Kawaami;T.Pruschke

我们分析了含阻挫的二维正方晶格的反铁磁Kondo晶格模型。近藤晶格模型在重费米子物理学的背景下特别有趣，因为它可能表现出反铁磁有序态和顺磁重费米子态之间的量子相变。根据电子性质，后者可以是在费米能量下动态产生平带的金属态，也可以是绝缘体，即所谓的近藤绝缘体。我们分析了次近邻（NNN）跳跃对近藤晶格模型性质的影响，特别是对半填充附近的顺磁和反铁磁性质的影响。为此，我们使用动力学平均场理论（DMFT）与数值重整化群（NRG）作为杂质求解器。当引入NNN跳跃时，顺磁结果保持定性不变，而在半填充时的Néel状态被自旋密度波取代。磁性有序态和近藤绝缘体之间的跃迁也依赖于NNN跳跃。NNN跳跃的一个有趣的效应是Néel态的稳定化远离半填充。

We analyze the antiferromagnetic Kondo lattice model for the two-dimensional square lattice including frustration. The Kondo lattice model is especially interesting in the context of heavy fermion physics, as it possibly exhibits a quantum phase transition between an antiferromagnetically ordered state and a paramagnetic heavy Fermion state. The latter can, depending on the electronic properties be either a metallic state with dynamically generated flat bands at the Fermi energy, or an insulator, the so-called Kondo insulator. We analyze the effects of next nearest neighbor (NNN) hopping upon the properties of the Kondo lattice model, especially focusing on the paramagnetic and antiferromagnetic properties around half filling. To this end we use the dynamical mean field theory (DMFT) with the Numerical Renormalization Group (NRG) as an impurity solver. Whereas the paramagnetic results remain qualitatively unchanged when introducing the NNN hopping, the Néel state at half filling is replaced by a spin-density wave. Also the transition between the magnetic ordered state and the Kondo insulator depends on the NNN hopping. An interesting effect of the NNN hopping is the stabilization of Néel states away from half filling.