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 similar to 2000% at 2 K. A large MR of similar to 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.

Automated summary

The study demonstrates an enhanced magnetoresistance effect in synthesized WTe2 single crystals. High crystallinity and tunable thickness of WTe2 single crystals are achieved by promoter-assisted chemical vapor deposition. The magnetoresistance of WTe2 shows a nonsaturating behavior with a positive MR of similar to 2000% at 2 K and a large MR of similar to 50% at 80 K.