Quasiparticles beyond the Fermi liquid and heavy fermion criticality
Quasiparticles beyond the Fermi liquid and heavy fermion criticality
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DOI：
10.1103/physrevb.84.041101
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发表时间：
2011-07-11
影响因子：
3.7
通讯作者：
Abrahams, Elihu
中科院分区：
文献类型：
--
作者：
Woelfle, Peter;Abrahams, Elihu
我们给出了一个自洽的理论的尺度相关的有效质量增强m*/m的准粒子的三维（3D）反铁磁（AFM）的自旋涨落的存在下，在AFM量子临界点的无序。临界准粒子理论描述了临界区域中费米子和玻色子自由度的耦合。利用这一事实，即使在“非费米液体”制度的准粒子的宽度不超过准粒子的能量，我们采用费米液体理论的关系，以确定依赖的自旋涨落谱的m*/m，从自能，从而m*/m可以计算。当初始值足够大时，m*/m的自洽方程具有强耦合解。我们认为，在YbRh_2Si_2，准二维AFM和/或三维铁磁高斯涨落存在于很宽的范围内驱动系统进入三维强耦合的波动制度。在T <0.3K的温度范围内，我们发现比热系数γ与T-1/4成正比的临界指数和电阻率ρ（T）= ρ（0）+ AT（3/4）的临界指数与YbRh_2Si_2的实验结果符合得很好。
We give a self-consistent theory of the scale-dependent effective mass enhancement m*/m of quasiparticles by three-dimensional (3D) antiferromagnetic (AFM) spin fluctuations in the presence of disorder at an AFM quantum critical point. The coupling of fermionic and bosonic degrees of freedom in the critical regime is described in terms of a critical quasiparticle theory. Using the fact that even in the "non-Fermi liquid" regime the quasiparticle width does not exceed the quasiparticle energy, we adopt relations from Fermi liquid theory to determine the dependence of the spin fluctuation spectrum on m*/m, from which the self-energy and hence m*/m may be calculated. The self-consistent equation for m*/m has a strong coupling solution provided the initial value is sufficiently large. We argue that in YbRh2Si2, quasi-2D AFM and/or 3D ferromagnetic Gaussian fluctuations existing over a wide range drive the system into the 3D strongly coupled fluctuation regime. We find critical exponents of the temperature dependence of the specific heat coefficient gamma proportional to T-1/4 and of the resistivity rho(T) = rho(0) + AT(3/4) in good agreement with experiments on YbRh2Si2 in the temperature range T < 0.3 K.