Large quadratic magnetoresistance caused by disorder in WTe2 nanoflakes

Abstract

The origin of large magnetoresistance (MR) in WTe2 has been extensively debated, with electron–hole compensation initially proposed as the dominant mechanism. Herein, we systematically investigate the magnetotransport properties of mechanically exfoliated WTe2 nanoflakes. A well-developed quadratic MR is observed, which cannot be explained by electron–hole compensation because the ratio of electron to hole concentration is greater than unity. Instead, the MR exhibits a strong correlation with the residual resistivity ratio, indicating disorder as a key factor. Considering the carrier inhomogeneity induced by disorder, we find that the quadratic MR follows a universal scaling behavior with the ratio of carrier concentration to its fluctuation, consistent with the effective-medium theory. These findings highlight the dominance of disorder in generating the large quadratic MR in WTe2 nanoflakes.