Ludicrous Magnetoresistance in WTe2
Magnetoresistance is the change of a material’s electrical resistance in response to an applied magnetic field. In addition to its intrinsic scientific interest, magnetoresistance is a technologically important property of matter, placing it clearly in ”‘Pasteur’s quadrant”’ Here we report the observation of a ludicrously large positive magnetoresistance (LMR) in the simple, non-magnetic, semi-metallic layered transition metal dichalcogenide, WTe2. Single crystals show a positive magnetoresistance of 452,000% at 4.5 Kelvin in an applied field of 14.7 Tesla, with no signs of impending saturation. The effect appears to turn on at temperatures between 50 and 100 K, but a low temperature electron diffraction study, where the effective field at the sample is on the order of 2 Tesla, shows that there is no structural phase transition or charge density wave accompanying this effect. The observations appear to be unprecedented, as no previous non-magnetic metals are known to show such a large positive magnetoresistance. We have no explanation to for the origin of the LMR, but electronic structure calculations show that WTe2 has a peculiar Fermi surface, with pairs of small hole and electron pockets in a direction corresponding to that of strongly bonded tungsten chains in the crystal structure. We propose that the determination of the origin of the effect and the fabrication of low temperature devices to detect magnetic fields with high sensitivity based on WTe2 will represent a significant new direction in the research and development of magnetoresistivity.
