磁基态重费密子系统的电阻反常  

RESISTIVITY ANOMALIES OF THE HEAVY FERMION SYSTEM WITH MAGNETIC GROUND STATES

作　　者：李正中[1] 苏为宁[1] 邱扬 

机构地区：[1]南京大学物理系,南京210008

出　　处：《物理学报》1990年第7期1154-1162,共9页Acta Physica Sinica

摘　　要：本文从周期性s-f交换模型出发,利用格林函数方法,研究了反铁磁基态Kondo晶格的电阻特性。首先在平均场近似下求出了此巡游电子系统的反铁磁序参量,然后超出平均场近似,用准至最发散对数阶(LLO)的微扰论方法,讨论了Kondo效应与反铁磁序之间的竞争。结果表明在Neel点(T_N)处出现电阻率极大是反铁磁Kondo晶格的特征之一,这与磁性重费密子材料(NpBe_(139)UCd_(11)和U_2Zn_(170))的电阻反常特征定性相符。此外,计算还表明Kondo温度与Neel温度的比值(T_K/T_N)强烈地调制电阻率的极大值,起着重费密子参量的作用。In the present article, the electrical resistance properties of the Kondo lattice with antiferromagnetic ground state are investigated from the periodic s-f exchange model by using the Green's function method. Firstly, we obtained the antiferromagnetic order parameter of this itinerant electron system in the mean field approximation (MFA), and then discussed the competition between the Kondo effect and antiferromagnetic ordering beyond the MFA by perturbative method to the leading logarithmic order (LLO). The results indicate that as one of the characteristic features of the antiferromagnetic Kondo lattice a resistivity maximum occurs at the Neel point(TN), which is in qualitative agreement with the anomalous properties in resistivity of the magnetic heavy fermion materials (NpBe13, UCd11, and U2Zn17). Furthermore, our calculation also shows that the ratio of the Kondo temperature and the Neel temperature (TK/TN) strongly modifies the maximum value of the resistivity, and thus plays the role of the heavy fermion parameter.

关 键 词：磁基态 重费密子系统 电阻反常 

分 类 号：O482.525[理学—固体物理]