Kondo destruction in heavy fermion quantum criticality and the photoemission spectrum of YbRh2Si2
Kondo destruction in heavy fermion quantum criticality and the photoemission spectrum of YbRh2Si2
复制标题
重费米子量子临界点的近藤破坏和 YbRh2Si2 的光电发射光谱
DOI：
10.1016/j.jmmm.2015.09.008
复制
发表时间：
2016-02-15
影响因子：
2.7
通讯作者：
Si, Q.
中科院分区：
文献类型：
--
作者：
Paschen, S.;Friedemann, S.;Si, Q.
重费米子金属为研究量子临界性提供了一个原型设置。在实验上，量子临界点已经在越来越多的重费米子化合物中被确定和研究。从理论上讲，近藤破坏提供了一种方法来表征一类超越序参数波动朗道框架的非常规量子临界点。对YbRh2Si2的测量是这种局部量子临界性的重要证据之一。在有限温度下，在霍尔系数和其他输运量和热力学量的等温场依赖性中观察到快速交叉，这在温度(T)-磁场(B)相图中指定了T*(B)线。在这里，我们通过分析交叉宽度与交叉位置的比率来讨论温度升高时会发生什么。随着该比值在T >= 0.5 K时趋于一致，YbRh2Si2在零磁场下属于量子临界涨落区，其中单粒子谱函数在大小费米表面上都具有显著的权重。这意味着，在这个温度范围内，任何对费米表面敏感的测量都将在大费米表面上看到显著的光谱权重。最近报道的YbRh2Si2在tbbb1k下的角分辨光谱学实验与这一预期一致，因此支持T*(B)线与近藤破坏物理的联系。(C) 2015 Elsevier B.V.版权所有
Heavy fermion metals provide a prototype setting to study quantum criticality. Experimentally, quantum critical points have been identified and studied in a growing list of heavy fermion compounds. Theoretically, Kondo destruction has provided a means to characterize a class of unconventional quantum critical points that goes beyond the Landau framework of order-parameter fluctuations. Among the prominent evidence for such local quantum criticality have been measurements in YbRh2Si2. A rapid crossover is observed at finite temperatures in the isothermal field dependence of the Hall coefficient and other transport and thermodynamic quantities, which specifies a T*(B) line in the temperature (T)-magnetic field (B) phase diagram. Here, we discuss what happens when temperature is raised, by analyzing the ratio of the crossover width to the crossover position. With this ratio approaching unity at T >= 0.5 K, YbRh2Si2 at zero magnetic field belongs to the quantum-critical fluctuation regime, where the single-particle spectral function has significant weight at both the small and large Fermi surfaces. This implies that, in this temperature range, any measurements sensitive to the Fermi surface will also see a significant spectral weight at the large Fermi surface. The angle-resolved photoemission spectroscopy experiments recently reported for YbRh2Si2 at T > 1 K are consistent with this expectation, and therefore support the association of the T*(B) line with the physics of Kondo destruction. (C) 2015 Elsevier B.V. All rights reserved.