Influence of electric fields on electronic specific heats of armchair and zigzag graphene ribbons

We use the tight-binding model to study the effect of transverse electric field on the electronic specific heat for armchair and zigzag graphene ribbons. For the zero field, the electronic specific heat exhibits rich temperature dependence, mainly owing to the special band structures. The thermal property strongly depends on the geometric structures, the edge structure and the width. There is a simple relation between the ribbon width and the electronic specific heat for the metallic or semiconducting armchair ribbons. However, it is absent for the zigzag ribbons. As for the presence of the electric fields, they change the energy dispersion, the density of states, and the electronic specific heat. Comparisons with the other systems are discussed. The predicted results could be verified by the experimental measurements.