Strange metal transport in electron-doped La_2-xCe_xCuO₄

I report measurements of normal state resistivity, Hall Effect, magnetoresistance, and thermopower in the electron-doped cuprate La_2-xCe_xCuO₄ for 0.19≥ x ≥0.08 as a function of temperature. The surprising results are:

The normal state magnetoresistance exhibits an anomalous linear-in-H behavior [1] at the same doping and temperature where a linear-in-T resistivity was previously observed for H>H_c2 [2].

The normal state Seebeck coefficient, S/T, exhibits an unconventional low temperature –lnT dependence at the same doping where linear-in-T and linear-in-H resistivity is found [3].
The normal state resistivity above Tc, from 80 K to 400 K, follows an anomalous ~A(x)T² behavior at zero field for all doping(x) [4].

The normal state resistivity upturn for doping x<0.14 can be completely suppressed above a certain magnetic field (H) and the exposed resistivity at high field has an anomalous linear-in-T dependence from 0.7K to ~40K and an anomalous linear-in-H magnetoresistance in the same temperature range [5].

I conclude that conventional Fermi liquid theory cannot explain any of these results. Moreover, the magnitude of the anomalous magnetoresistance and thermopower scales with Tc, suggesting that the origin of the superconductivity is correlated with the strange metal normal state properties. the low temperature linear-in-T resistivity, a hallmark of the strange metallic state, is a universal feature of the n-doped cuprates for doping within the SC dome.

1. T. Sarkar et al., Sci. Adv. 5, eaav6753 (2019).
2. Richard L. Greene, et al., ARCMP 11, 213 (2020).
3. P. R. Mandal et al., PNAS 116, 5991 (2019).
4. T. Sarkar, R. L. Greene, and SD Sarma, PRB 98, 224503 (2018).
5. T. Sarkar et al., arXiv:2007.12765 (2020).