Enhanced Magnetoresistance of Doped WTe₂ Single Crystals

Magnetoresistance (MR), a change of electrical resistance in response to an external magnetic field, revolutionizes the fundamental study of spintronics and leads to applications in solid-state memory devices. Tungsten ditelluride (WTe2) exhibits an extremely large MR below 10 K and is highlighted to explore unique properties at high temperatures, such as ferroelectricity at 300 K and the quantum spin Hall effect at 100 K. However, these remarkable phenomena only appear in the exfoliated crystals protected by h-BN encapsulation. Here, an enhanced MR is demonstrated in the synthesized WTe2 single crystals. The high crystallinity and tunable thickness of the WTe2 single crystals are achieved by promoter-assisted chemical vapor deposition. The MR of WTe2 shows a nonsaturating behavior with a positive MR of ∼2000% at 2 K. A large MR of ∼50% is observed at 80 K in the as-grown single crystals, which is comparable to that of bulk WTe2 and experimentally achieved for the first time. Moreover, the MR is further enhanced by fluoropolymer encapsulation, which effectively induces p-doping in WTe2 for promoting carrier compensation. This work indicates the synthesized WTe2 single crystals as a promising candidate for next-generation spintronics devices.