Tuning of electronic density-of-states singularities is a common route to unconventional metal physics. Conceptually, van Hove singularities are realized only in clean two-dimensional systems. Little attention has therefore been given to the disordered (dirty) limit. Here, we provide a magnetotransport study of the dirty metamagnetic system calcium-doped strontium ruthenate. Fermi liquid properties persist across the metamagnetic transition, but with an unusually strong variation of the Kadowaki-Woods ratio. This is revealed by a strong decoupling of inelastic electron scattering and electronic mass inferred from density-of-state probes. We discuss this Fermi liquid behavior in terms of a magnetic field tunable van Hove singularity in the presence of disorder. More generally, we show how dimensionality and disorder control the fate of transport properties across metamagnetic transitions.

电子态密度奇异性的调整是通向非常规金属物理的常见途径。从概念上讲，van Hove奇异性仅在干净的二维系统中实现。因此，对无序（脏污）限值的关注很少。在这里，我们提供了一个肮脏的超磁系统中掺入钌酸锶锶的磁传输研究。费米液体性质在整个超磁跃变过程中一直保持不变，但其卡多瓦基—伍兹比值却出现了异常强烈的变化。非弹性电子散射和从状态密度探针推断出的电子质量之间的强解耦关系揭示了这一点。我们根据存在场的磁场可调范霍夫奇点讨论这种费米液体行为。更普遍，