Unconventional large linear magnetoresistance in Cu2−xTe

Abstract

We report a large linear magnetoresistance in Cu2−xTe, reaching Δρ/ρ(0) = 250% at 2 K in a 9 T field, for samples with x = 0.13 to 0.22. These results are comparable to those for Ag2X materials, though for Cu2−xTe the carrier densities are considerably larger. Examining the magnitudes and the crossover from quadratic to high-field linear behavior, we show that models based on classical transport behavior best explain the observed results. The effects are traced to the misdirection of currents in high mobility transport channels, likely due to behavior at grain boundaries such as topological surface states or a high mobility interface phase. The resistivity also exhibits a T2 dependence in the temperature range where the large linear MR appears, an indicator of electron-electron interaction effects within the high mobility states. Thus this is an example of a system in which electron-electron interactions dominate the low-temperature linear magnetoresistance.