Electrical transport phenomena in two-dimensional metallic 2H-NbSe₂: an experimental and theoretical study

Two-dimensional (2D) metallic transition metal dichalcogenides (TMDCs) have attracted extensive interest in various fields owing to their unique electronic properties. However, studies on their transport properties and the modulation of these properties based on their band structure are limited. Herein, we studied the transport phenomena in 2D metallic 2H-NbSe₂ using experimental and theoretical approaches. The transport properties, including electrical conductivity (σ) and Seebeck coefficient (S), of mechanically exfoliated 2H-NbSe₂ nanosheets were measured. We observed field effect-dependent variations in σ and S of the 2H-NbSe₂ nanosheets. Theoretical calculations of the electronic band structures and estimations of the transport properties of 2D 2H-NbSe₂ crystals were conducted to verify and explain the experimental results. The superconducting transition temperature of the exfoliated NbSe₂ nanosheets validated the reliability of the sample preparation procedures and indicated the high quality of the samples. Our findings provide a basis for understanding the electrical properties of metallic TMDCs intended for various applications.