Hidden strange metallic state in underdoped electron-doped cuprates*

The low-temperature linear-in-T resistivity of “strange metals,” such as the metallic state of the cuprate high-temperature superconductors, has long been thought to be associated with a quantum critical point. However, recent transport studies of the cuprates have found this behavior persists over a wide range of overdoping. In this work [1], we report magnetoresistance and Hall effect results for electron-doped cuprate La_{2− x}Ce_xCuO₄ for temperatures from 0.7 to 45 K and magnetic fields up to 65 T. For x= 0.12 and 0.13, just below the Fermi surface reconstruction (FSR) at x= 0.14, the normal state in-plane resistivity exhibits a well-known upturn at low temperature. Our new results show that this resistivity upturn is eliminated at a high magnetic field and the resistivity becomes linear-in-temperature. The magnitude of the linear coefficient scales with T_c and doping, as found previously [2,3] for dopings above the FSR. This finding suggests that the strange metal is not confined to a single “critical point” in the phase diagram, but rather is a robust universal feature of the metallic ground state of the cuprates.

1. T. Sarkar, et al., Phys. Rev. B 103, 224501 (2021).

2. K. Jin,  et al.,Nature(London) 476, 73 (2011).

3. T. Sarkar, et al., Sci. Adv. 5, eaav6753 (2019).