Thermoelectric power of heavy-fermion compounds
Thermoelectric power of heavy-fermion compounds
复制标题
重费米化合物的热电势
DOI：
10.1007/bf01321909
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
K. Fischer
中科院分区：
文献类型：
--
作者：
K. Fischer
我们计算了安德森晶格的扩散热势作为模型的重费米子化合物在半唯象理论。在这个理论中，热电势用描述自旋涨落的动态磁化率来表示，并且可以通过中子散射来测量。近藤效应被考虑为一个单电子自旋，这是耦合到所有其他自旋和传导电子。这种方法忽略了传导电子的多次内禀散射。我们得到了一个“近藤”项S（1）d（T）（其中非相互作用自旋的热电势乘以一个描述自旋动力学的因子）和一个相反符号的“共振”项S（2）d（T），它在相互作用消失时消失。这两项的叠加导致了一个广泛的最大热电势大致在近藤temperatureTK和一个额外的最小值belowTK。当T →0时，S（1）d项变为T 2，S（2）d项变为T的正比。我们还表明，索末菲展开导致一个不正确的结果的低温电阻率的安德森晶格和Gorter-Nordheim关系并不持有在低温下。
We calculate the diffusion thermopower of the Anderson lattice as a model for heavyfermion compounds in a semi-phenomenological theory. In this theory, the thermopower is expressed by the dynamical susceptibility which describes spin fluctuations and can be measured by neutron scattering. The Kondo effect is taken into account for a singlef-electron spin which is coupled to all other spins and to the conduction electrons. This approach neglects multiple intesite-scattering of the conduction electrons. We obtain a “Kondo” termS(1)d(T) (in which the thermopower of non-interacting spins is multiplied by a factor which describes the spin dynamics) and a “resonance” termS(2)d(T) of opposite sign which vanishes for vanishing interactions. The superposition of both terms leads to a broad maximum of the thermopower roughly at the Kondo temperatureTKand to an additional minimum belowTK. ForT→0 the termS(1)dvanishes asT2and the termS(2)dbecomes proportional toT. We also show that the Sommerfeld expansion leads to an incorrect result for the low temperature resistivity of the Anderson lattice and that the Gorter-Nordheim relation does not hold at low temperatures.