Quantum-mechanical fluctuations between competing phases induce exotic collective excitations that exhibit anomalous behavior in transport and thermodynamic properties, and are often intimately linked to the appearance of unconventional Cooper pairing. High-temperature superconductivity, however, makes it difficult to assess the role of quantum-critical fluctuations in shaping anomalous finite-temperature physical properties. Here we report temperature-field scale invariance of non-Fermi liquid thermodynamic, transport, and Hall quantities in a non-superconducting iron-pnictide, Ba(Fe_1/3Co_1/3Ni_1/3)₂As₂, indicative of quantum criticality at zero temperature and applied magnetic field. Beyond a linear-in-temperature resistivity, the hallmark signature of strong quasiparticle scattering, we find a scattering rate that obeys a universal scaling relation between temperature and applied magnetic fields down to the lowest energy scales. Together with the dominance of hole-like carriers close to the zero-temperature and zero-field limits, the scale invariance, isotropic field response, and lack of applied pressure sensitivity suggests a unique quantum critical system unhindered by a pairing instability.

竞争相之间的量子力学波动会引起奇异的集体激发，这些激发在输运和热力学性质方面表现出异常行为，并且通常与非常规库珀配对的出现密切相关。然而，高温超导使得难以评估量子临界波动在塑造异常的有限温度物理特性中的作用。在这里，我们报告了非超导铁氧体Ba（Fe _1/3 Co _1/3 Ni _1/3）₂ As ₂中非费米液体的热力学，输运和霍尔量的温度场尺度不变性。表示零温度和外加磁场下的量子临界。除了温度线性电阻率（强准粒子散射的标志性特征）之外，我们发现散射速率服从温度和施加的磁场之间的通用比例关系，并降至最低的能量范围。加上接近零温度和零磁场极限的孔状载流子的优势，尺度不变性，各向同性场响应以及所施加的压力敏感性不足，表明独特的量子临界系统不受配对不稳定的影响。