Cai Ang, Yu Zuodong, Hu Haoyu, Kirchner Stefan, Si Qimiao
Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA.
Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou, Zhejiang 310058, China.
Phys Rev Lett. 2020 Jan 17;124(2):027205. doi: 10.1103/PhysRevLett.124.027205.
Quantum critical points often arise in metals perched at the border of an antiferromagnetic order. The recent observation of singular and dynamically scaling charge conductivity in an antiferromagnetic quantum critical heavy fermion metal implicates beyond-Landau quantum criticality. Here we study the charge and spin dynamics of a Kondo destruction quantum critical point (QCP), as realized in an SU(2)-symmetric Bose-Fermi Kondo model. We find that the critical exponents and scaling functions of the spin and single-particle responses of the QCP in the SU(2) case are essentially the same as those of the large-N limit, showing that 1/N corrections are subleading. Building on this insight, we demonstrate that the charge responses at the Kondo destruction QCP are singular and obey ω/T scaling. This property persists at the Kondo destruction QCP of the SU(2)-symmetric Kondo lattice model.
量子临界点通常出现在处于反铁磁序边界的金属中。最近在一种反铁磁量子临界重费米子金属中观测到奇异且动态标度的电荷电导率，这暗示了超越朗道的量子临界性。在此，我们研究了在一个SU(2)对称玻色 - 费米近藤模型中实现的近藤破坏量子临界点（QCP）的电荷和自旋动力学。我们发现，在SU(2)情形下，该QCP的自旋和单粒子响应的临界指数及标度函数与大N极限情形下的基本相同，这表明1/N修正项是次要的。基于这一见解，我们证明了近藤破坏QCP处的电荷响应是奇异的且服从ω/T标度。这一性质在SU(2)对称近藤晶格模型的近藤破坏QCP处依然存在。
