First Principle Study of Alkaline Metal Intercalation in Twisted Bilayer Graphene

TL;DR

This study investigates how alkaline metal intercalation and twist angles in bilayer graphene influence electronic and thermal properties, revealing tunable bandgaps and transport characteristics for potential applications.

Contribution

It provides a first-principles analysis of how intercalation and twist angles modulate the electronic and thermal properties of bilayer graphene.

Findings

Bandgap increases with twist angle.

Seebeck and Hall coefficients increase with twist angle.

Thermal and electrical conductivities decrease with twist angle.

Abstract

The intercalant alkaline metals, Ca, Sr, & Ba, are sources of a periodic perturbation on the bilayer graphene, which leads to the formation of an N-type semiconductors. The twist angle between graphene layers applies disorder to the intercalated bilayer graphene to tune the bandgap. The twisted bilayer graphene structures of C8MC8 (M: Ca, Sr, Ba) were studied for the Energy band diagrams, Density of States, transport properties of Seebeck coefficient, Hall coefficient, Thermal conductivity, and Electrical conductivity using Quantum-Espresso and BoltzTrap software. The bandgap enhances with respect to an increase in twist angle to values of technological requirements to implement in real applications. The peak of the Seebeck coefficient & Hall Effect increase, and Thermal Conductivity & Electrical Conductivity decrease for different twist angles. Therefore, C8MC8 has a significant impact of the twist angle, hence gives possible tailoring of material properties.