Investigation of Bond Energy Effect on the Electronic Band Structure of Penta-Graphene using Tight-Binding Method

Abstract

Graphene is a semiconductor with zero band-gap, meaning that the energy difference between the valence band and conduction band is zero. This characteristic is not a good feature for making electronic devices such as transistors and sensors. Therefore, by changing the structure of graphene, a new sample of graphene as “penta graphene” with a non-zero band-gap can be obtained. Penta graphene as a new and stable carbon allotrope is stronger than graphene. It is a nonconductor material in which the transfer of electrons from the valence band to the conduction band is very low. In this research, an attempt has been made by solving the Schrödinger equation for two bond energies t and tp and finally by equating these two energies in the equation, two bands of valence and conduction in penta graphene meet at two points and there is an overlap in this case. Considering the real part of the roots and regardless of their imaginary part, the diagrams of energy E as a function of wave vector k can be obtained for different amounts of bond energy. The results demonstrate that by increasing the value of t, the band gap decreases and there is an overlap between the conduction and valance bands.