Direct Evidence for Charge Compensation-Induced Large Magnetoresistance in Thin WTe₂

Abstract

Since the discovery of extremely large non-saturating magnetoresistance (MR) in WTe2, much effort has been devoted to understanding the underlying mechanism, which is still under debate. Here, we explicitly identify the dominant physical origin of the large non-saturating MR through in-situ tuning of the magnetotransport properties in thin WTe2 film. With an electrostatic doping approach, we observed a non-monotonic gate dependence of the MR. The MR reaches a maximum (10600%) in thin WTe2 film at certain gate voltage where electron and hole concentrations are balanced, indicating that the charge compensation is the dominant mechanism of the observed large MR. Besides, we show that the temperature dependent magnetoresistance exhibits similar tendency with the carrier mobility when the charge compensation is retained, revealing that distinct scattering mechanisms may be at play for the temperature dependence of magneto-transport properties. Our work would be helpful for understanding mechanism of the large MR in other nonmagnetic materials and offers an avenue for achieving large MR in the non-magnetic materials with electron-hole pockets.

Synthesis of tungsten ditelluride thin films and highly crystalline nanobelts from pre-deposited reactants

“…Applications-centred studies of WTe 2 have historically focused on thermoelectrics but more recent studies have examined a much broader range of potentially interesting properties and applications. Experimental investigations of the electronic properties of WTe 2 have demonstrated large, non-saturating magnetoresistance and high charge-carrier mobilities of up to 10,000 cm 2 •V −1 •s −1 [14][15][16]. There are also reports of ferroelectricity [17] and superconductivity [18,19] in WTe 2 .…”

“…The majority of reports, especially those examining its electronic properties, have focused on mechanically exfoliated flakes from chemical vapour transport (CVT)-grown crystals of WTe 2 [14][15][16][31][32][33]. While CVT does produce exceptionally high-quality crystals, it is a time-and energyintensive process requiring long anneals at temperatures of up to 1000 °C.…”

Surface band bending in semimetal Td-WTe2

“…3 f. After subtracting Shirley background, the spectra collected under different TOAs were tted using Eqs. (1) and (2) in Method with the tting parameters: binding energy E 0 , strength of the electrostatic potential K, the ratio of Gaussian function α, and the full width at half maximum F. The tted curves were displayed in Fig. 3b and Fig.…”

“…As a layered transition metal dichalcogenide (TMD), tungsten ditelluride (WTe 2 ) crystallizes in a distorted orthorhombic structure (space group: Pnm2 1 ), named T d -WTe 2 here. Both bulk and monolayer 1T -WTe 2 have spurred tremendous studies due to intriguing properties, including large magnetoresistance, 1,2 nonlinear anomalous Hall effect, 3 superconductivity, [4][5][6][7] quantum spin Hall behavior [8][9][10] and type-II Weyl semimetal. [11][12][13] Recently, spontaneous out-of-plane electric polarization and ferroelectric switching were observed in two-and three-layer WTe 2 .…”

Preparation and Crystal Growth of Transition Metal Dichalcogenides

“…[170] On (b): WSe 2 crystals can also be obtained from various fluxes (PbCl 2 , Bi, Sb, Te). [134] WTe 2 : (a) [83,180,306] , (c) [181] On (a): WTe 2 has been known for almost than 100 years. [182] It was characterized by X-ray diffraction in 1956.…”