Taupin Mathieu, Paschen Silke
Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria;
Crystals (Basel). 2022 Feb 12;12(2):251. doi: 10.3390/cryst12020251. eCollection 2022 Feb.
Strange metal behavior refers to a linear temperature dependence of the electrical resistivity that is not due to electron-phonon scattering. It is seen in numerous strongly correlated electron systems, from the heavy fermion compounds, via transition metal oxides and iron pnictides, to magic angle twisted bi-layer graphene, frequently in connection with unconventional or "high temperature" superconductivity. To achieve a unified understanding of these phenomena across the different materials classes is a central open problem in condensed matter physics. Tests whether the linear-in-temperature law might be dictated by Planckian dissipation-scattering with the rate -are receiving considerable attention. Here we assess the situation for strange metal heavy fermion compounds. They allow to probe the regime of extreme correlation strength, with effective mass or Fermi velocity renormalizations in excess of three orders of magnitude. Adopting the same procedure as done in previous studies, i.e., assuming a simple Drude conductivity with the above scattering rate, we find that for these strongly renormalized quasiparticles, scattering is much weaker than Planckian, implying that the linear temperature dependence should be due to other effects. We discuss implications of this finding and point to directions for further work.
奇异金属行为是指电阻率与温度呈线性关系，且这种关系并非由电子 - 声子散射引起。在众多强关联电子系统中都能观察到这种现象，从重费米子化合物，到过渡金属氧化物、铁基超导体，再到魔角扭曲双层石墨烯，这种现象常常与非常规或“高温”超导性相关联。要对不同材料类别中的这些现象达成统一理解，是凝聚态物理中的一个核心开放性问题。关于温度线性规律是否可能由具有特定速率的普朗克耗散散射所决定的测试正受到广泛关注。在此，我们评估奇异金属重费米子化合物的情况。它们能够探测极端关联强度的区域，其有效质量或费米速度重整化超过三个数量级。采用与先前研究相同的程序，即假设具有上述散射速率的简单德鲁德电导率，我们发现对于这些强重整化的准粒子，散射比普朗克散射弱得多，这意味着线性温度依赖关系应由其他效应引起。我们讨论了这一发现的意义，并指出了进一步研究的方向。
