Phenomenology of ESR in heavy-fermion systems: Fermi-liquid and non-Fermi-liquid regimes
Phenomenology of ESR in heavy-fermion systems: Fermi-liquid and non-Fermi-liquid regimes
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重费米子系统中 ESR 的现象学：费米液体和非费米液体状态
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
E. Abrahams
中科院分区：
文献类型：
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作者：
P. Woelfle;E. Abrahams
我们扩展和应用最近的安德森晶格系统的动态自旋响应理论来解释电子自旋共振（ESR）数据${ 联系我们 ext{Si}}_{2}$。从低温T_l {T}_{x}$（一个交叉温度）和低磁场$B_l {B}_{x}$下的半唯象费米液体描述出发，通过采用一个有效质量和自旋磁化率随能量/温度呈幂律变化的准粒子图像，将描述扩展到非费米液体区域。我们发现一个尖锐的ESR共振线从本地$F$-水平共振略有位移和扩大准粒子散射（采取不平等的$G$因素的传导和$F$电子）和自旋晶格弛豫，都显着减少铁磁波动的影响。我们的理论与数据的详细比较显示出良好的协议在费米液体制度。在非费米液体制度，我们发现一个密切的关系的$T$依赖的比热/自旋磁化率与所观察到的$T$依赖的线位移和线宽。
We extend and apply a recent theory of the dynamical spin response of Anderson lattice systems to interpret electron-spin resonance (ESR) data on ${ ext{YbRh}}_{2}{ ext{Si}}_{2}$. Starting within a semiphenomenological Fermi-liquid description at low temperatures $Tl{T}_{x}$ (a crossover temperature) and low magnetic fields $B⪡{B}_{x}$, we extend the description to the non-Fermi-liquid regime by adopting a quasiparticle picture with effective mass and spin susceptibility varying logarithmically with energy/temperature as observed in experiment. We find a sharp ESR resonance line slightly shifted from the local $f$-level resonance and broadened by quasiparticle scattering (taking unequal $g$ factors of conduction and $f$ electrons) and by spin-lattice relaxation, both significantly reduced by the effect of ferromagnetic fluctuations. A detailed comparison of our theory with the data shows excellent agreement in the Fermi-liquid regime. In the non-Fermi-liquid regime we find a close relation of the $T$ dependence of the specific-heat/spin susceptibility with the observed $T$ dependence of line shift and linewidth.