High Temperature Electrical Transport in Electron-Doped Cuprates

Although the origin of high-temperature superconductivity in the cuprates has eluded the community for decades, the normal state of these materials is similarly enigmatic. The universal T-linear electrical resistivity observed in hole-doped compounds such as YBCO and LSCO, persistent to high temperatures, is thought to violate the Mott-Ioffe-Regel (MIR) limit on the scattering rate, where traditional Boltzmann theories of transport break down. Consequently, the normal state of these and other strongly correlated materials are now considered a new phase of matter, the "strange metal." We report resistivity and magnetoresistivity (MR) measurements of the electron doped cuprate La_2-xCe₂CuO₄ (LCCO) from 100K to above room temperature and relate our findings to the hole-doped side of the phase diagram. By studying slightly underdoped samples (x=.08, .10) in proximity to the antiferromagnetic phase (without a field), we are able probe the strange metallic regime in the vicinity of the MIR bound without having to resort to excessively high temperatures. For other dopings, we report new MR data.