Anomalous normal state magnetotransport in an electron-doped cuprate

TL;DR

This study reveals unconventional magnetotransport behaviors in electron-doped cuprates, including a non-standard magnetic field dependence of magnetoresistance and doping-dependent Hall angle variations, suggesting complex underlying electronic states.

Contribution

It provides comprehensive magnetotransport measurements across various dopings, uncovering anomalous behaviors linked to high-temperature resistivity and Fermi surface changes in electron-doped cuprates.

Findings

Unconventional $ ext{H}^{3/2}$ magnetoresistance above 100 K.

Violation of Kohler's rule in magnetoresistance.

Doping-dependent $ ext{cot} heta_H$ with distinct temperature exponents.

Abstract

We report magnetoresistance and Hall angle measurements of the electron-doped cuprate La$_{2-x}$Ce$_x$CuO$_4$ over a wide range of dopings from $x = 0.08 - 0.17$. Above 100 K, we find an unconventional $\sim H^{3/2}$ magnetic field dependence of the magnetoresistance observed in all samples doped within the superconducting dome. Further, the measured magnetoresistance violates Kohler's rule. Given the ubiquity of this anomalous magnetoresistance at high temperatures above the superconducting dome, we speculate that the origin of this behavior is linked to the unusual $\rho \sim T^2$ resistivity observed over the same wide parameter range at high temperatures. We also find a strong doping dependence of the Hall angle with an unconventional temperature dependence of $\cot \theta_H \sim T^{4}$ ($T^{2.5}$) for samples doped below (above) the Fermi surface reconstruction doping $x_{\text{FSR}} = 0.14$.