Mott variable-range hopping transport in a MoS₂ nanoflake

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• Understanding charge transport in low-dimensional materials is crucial for electronic applications.
• Disordered multilayered molybdenum disulfide (MoS2) nanoflakes present unique transport properties due to their complex structure.

Purpose of the Study:

• To investigate the electrical and magnetotransport characteristics of disordered, multilayered MoS2 nanoflakes in the insulator regime.
• To elucidate the dominant charge transport mechanisms across a wide temperature range.

Main Methods:

• Electrical transport measurements using a four-probe setup.
• Magnetoresistance measurements under varying magnetic fields and temperatures.
• Exfoliation of MoS2 nanoflakes from bulk MoS2 crystals.

Main Results:

• At high temperatures, conductance (G) follows a ln G ~ -T^-1 dependence, indicating thermal activation.
• At low temperatures, conductance exhibits a ln G ~ -T^-1/3 dependence, characteristic of two-dimensional (2D) Mott variable-range hopping (VRH).
• Low-field magnetoresistance shows a quadratic magnetic field dependence (~ αB^2 with α ~ T^-1), consistent with 2D Mott VRH.

Conclusions:

• The study confirms 2D Mott VRH as the dominant transport mechanism in disordered MoS2 nanoflakes at low temperatures.
• Magnetotransport measurements provide strong evidence supporting the observed VRH transport behavior.
• These findings contribute to the understanding of charge transport in complex 2D materials.