Electronic Structures of Two-Dimensional PC6-Type Materials

TL;DR

This paper investigates how chemical functionalization of 2D PC6 materials can shift their Fermi level to access Dirac points, enabling potential electronic applications of these intriguing band structures.

Contribution

It introduces methods to tune the Fermi level in 2D PC6 materials through heteroatom substitution and hydrogen adatoms, revealing new ways to access Dirac points.

Findings

Substitution with heteroatoms shifts the Fermi level to access Dirac points.

Hydrogen adatoms increase electron filling and raise the Fermi level.

PC6's band structure can be tuned via chemical functionalization.

Abstract

Two-dimensional (2D) materials may exhibit intriguing band structure features (e.g., Dirac points), that lay far away from the Fermi level. They are, thus, not usable in applications. The semiconducting 2D material PC6 has two Dirac cones above and below the Fermi level. Therefore, it is an ideal playground to demonstrate chemical functionalization methods for shifting the Fermi level in order to access interesting band structure features. PC6 is based on the sqrt(7) x sqrt(7)R19.1deg super cell of graphene with two carbon atoms per unit cell substituted by phosphorous. It is demonstrated how substitution with other heteroatoms that contain a different number of valence electrons, the Dirac points can be accessed. Alternatively, hydrogen atoms can be used as adatoms at the heteroatom sites. This increases electron filling and shifts the Fermi level upwards.