Diffusive Electronic Transport Coefficients of Graphene/Bi2Se3 Heterostructures: Insights from First-Principles Calculations.

Two-dimensional (2D) materials have emerged as versatile platforms for exploring novel physical phenomena, particularly in electronic and thermoelectric transport, where reduced dimensionality enables confinement effects that provide enhanced control over fundamental properties. In this context, van der Waals heterostructures offer a strategic route to engineering these properties via proximity effects. In this work, we investigate Graphene (G)/Bi2Se3 heterostructures, experimentally accessible monolayers, by means of density functional theory (DFT) calculations, including spin-orbit coupling (SOC) and van der Waals corrections. Two stacking configurations, eclipsed and staggered arrangements, are considered, both with favorable interlayer binding energies that confirm the stability of the interface. Our results, globally similar for both configurations, show that the physical response is dominated by interfacial coupling, which induces significant charge transfer resulting from the competition between the work functions of the individual components and the formation of an interface dipole. This charge transfer results in a metallic character in the heterostructures with an upward Dirac cone shift. Furthermore, SOC and band hybridization increase the complexity of the electronic structure, leading to features such as band splittings and avoided crossings due to proximity interactions. These combined effects give rise to an enhancement of both electrical and electronic thermal conductivities; however, they reduce the Seebeck coefficient and the electronic figure of merit ZT(e), revealing a thermoelectric trade-off. Overall, we find that these heterostructures are better suited for efficient charge transport and heat dissipation than for thermoelectric energy conversion, underscoring how proximity effects can be exploited to tailor the functional limits of 2D systems.