The origin of T-linear resistivity in strange metal compounds has been subject to debate for years. Initially, T-linear resistivity was believed to come from specific regions with T-linear scattering rate over the Fermi surface [1], but more recently it was showed – in the strange metal phase of hole-doped cuprate Nd-LSCO – that it actually comes from a fully isotropic scattering rate with a Planckian value at [2]. However, the proximity of strange metal Nd-LSCO to a van Hove singularity makes the Fermi surface highly anisotropic, which has complicated the interpretation of these results. To resolve this ambiguity, we study electron-doped cuprates – that exhibit a completely isotropic Fermi surface in the strange metal regime – using angle-dependent magnetoresistance measurements. Experiments were performed under a 41.5 T field at the National High Magnetic Field Laboratory in Tallahassee on NCCO x=0.17, and the scattering rate was extracted from the data using Boltzmann transport calculations. Our results show a scattering rate that can be divided into two parts: one, isotropic, T-linear and Planckian, reinforcing previous findings on hole-doped cuprates [2], and the other, anisotropic and related to antiferromagnetic hotspots on the Fermi surface. This further supports the idea that strange metal behaviour emerges from interactions between all electrons of the Fermi surface and not from some isolated regions. To conclude our findings, we were able to reproduce the Hall effect of electron-doped cuprates – which mysterious sign change in temperature is inexplicable by the shape of its Fermi surface – using a hot spot model. We present the data, calculations and our models.

[1] Abdel-Jawad et al. Nature Physics (2006).