Origin of the turn-on temperature behavior in WTe2.

A hallmark of materials with extremely large magnetoresistance (XMR) is the transformative turn-on temperature behavior: when the applied magnetic field H is above certain value, the resistivity versus temperature ρ(T ) curve shows a minimum at a field dependent temperature T ∗, which has been interpreted as a magnetic-field-driven metal-insulator transition or attributed to an electronic structure change. Here, we demonstrate that ρ(T ) curves with turn-on behavior in the newly discovered XMR material WTe2 can be scaled as MR ∼ (H/ρ0) m with m ≈ 2 and ρ0 being the resistivity at zero field. We obtained experimentally and also derived from the observed scaling the magnetic field dependence of the turn-on temperature T ∗ ∼ (H − Hc) ν with ν ≈ 1/2, which was earlier used as evidence for a predicted metal-insulator transition. The scaling also leads to a simple quantitative expression for the resistivity ρ∗ ≈ 2ρ0 at the onset of the XMR behavior, which fits the data remarkably well. These results exclude the possible existence of a magnetic-field-driven metal-insulator transition or significant contribution of an electronic structure change to the low-temperature XMR in WTe2. This work resolves the origin of the turn-on behavior observed in several XMR materials and also provides a general route for a quantitative understanding of the temperature dependence of MR in both XMR and non-XMR materials.