Enhancement of the thermoelectric properties in bilayer graphene structures induced by Fano resonances

TL;DR

This study investigates how Fano and hybrid resonances in bilayer graphene structures can significantly enhance thermoelectric properties like the Seebeck coefficient and power factor, suggesting potential for improved thermoelectric devices.

Contribution

It demonstrates the impact of Fano and hybrid resonances on thermoelectric performance in bilayer graphene barriers, including the effects of bandgap size.

Findings

Fano resonances lead to Seebeck coefficients of tens of mV/K.

Power factor reaches the order of nW/K in resonance conditions.

Increasing bandgap reduces thermoelectric efficiency despite resonance profiles.

Abstract

Fano and hybrid resonances of bilayer graphene could be attractive for thermoelectric devices. The special profile presented by such resonances could significantly enhance the Seebeck coefficient and the power factor. In this work, we study the thermoelectric properties of bilayer graphene single and double barrier structures. The charge carriers are described as massive chiral particles through an effective Dirac-like Hamiltonian. The Hybrid matrix method, the Landauer-B\"{u}ttiker formalism and the Cutler-Mott formula are implemented to obtain the transmission, transport and thermoelectric properties, respectively. The Seebeck coefficient and the power factor are analyzed for gapless and gapped single and double barriers. We find that in the energy range where Fano resonances occur, the Seebeck coefficient attains values of tens of mV/K and the power factor reaches values of the order nW/K. Hybrid resonances also sustain high values for the thermoelectric properties, however not as high as Fano resonances. We also find that despite the Fano and hybrid profiles are manifested in the conductance of gapped barrier structures, the Seebeck coefficient and the power factor are systematically reduced as the bandgap gets larger. So, our findings indicate that bilayer graphene barrier structures can be used to improve the response of thermoelectric devices.