Tunable excitons in rhombohedral trilayer graphene

Trilayer graphene is receiving an increasing level of attention due to its stacking-dependent magnetoelectric and optoelectric properties more robust ferromagnetism relative monolayer bilayer variants. Additionally, rhombohedral stacked trilayer presents the possibility easily opening a gap via either external electric field perpendicular layers or application strain. In this paper, we consider open band in study excitonic optical response system. This done combination tight-binding model with Bethe--Salpeter equation solved semianalytically requiring only simple numerical quadrature. We then discuss valley-dependent selection rules followed by computation linear conductivity for case encapsulated hexagonal boron nitride. The tunability resonances also discussed together localization states as increases.