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

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• Extremely large nonsaturating magnetoresistance (MR) in WTe2 has been observed.
• The underlying physical mechanism for this phenomenon remains under debate.

Purpose of the Study:

• To explicitly identify the dominant physical origin of large nonsaturating MR in WTe2 films.
• To investigate the role of charge compensation and carrier mobility in MR.

Main Methods:

• In situ tuning of magneto-transport properties in thin WTe2 films.
• Electrostatic doping approach to modify carrier concentrations.
• Analysis of gate dependence and temperature dependence of MR.

Main Results:

• Observed a nonmonotonic gate dependence of MR, peaking at charge balance.
• Achieved a maximum MR of 10600% in thin WTe2 films.
• Demonstrated that charge compensation is the dominant mechanism for large MR.
• Found similar temperature dependence for MR and carrier mobility when charge compensation is maintained.

Conclusions:

• Charge compensation is identified as the dominant mechanism for large nonsaturating MR in WTe2.
• Distinct scattering mechanisms may influence the temperature dependence of magneto-transport properties.
• Provides a pathway for achieving large MR in nonmagnetic materials with electron-hole pockets.