Introducing Holes into Graphene Could Enable Its Use in Spintronics Applications

In its regular form, graphene cannot be used as an alternative to silicon chips for nanoelectronics applications. Its energy band structure is well known, leaving no magnetic effects and no energy gap.

However, graphene antidot lattices are an innovative type of graphene device, containing a periodic array of holes—lacking a number of atoms in the otherwise regular single layer of carbon atoms. Due to this, an energy band gap opens up close to the baseline energy level of the material, thus making graphene an effective semiconductor. In an innovative research reported in EPJ B, Iranian physicists have analyzed the influence of antidot size on the electronic structure and magnetic properties of triangular antidots in graphene.

The team of Zahra Talebi Esfahani from Payame Noor University in Tehran, Iran, has validated the occurrence of a band gap opening in such antidot graphene lattices, which is dependent on the spin degree of freedom of the electron and which could be made use of in applications such as spin transistors. In order to investigate the effects of both the zigzag-shaped and armchair-shaped edges of graphene holes on the properties of the material, the researchers carried out simulations using holes that are shaped like equilateral and right triangles.

Through this study, the researchers found that the values of the energy band gap and the total magnetization are dependent on the shape, size, and spacing of the antidots. These may, in fact, increase with increase in the number of zigzag edges surrounding the holes. The induced magnetic moments are primarily localized on the edge atoms, with a maximum value at the center of each side of the equilateral triangle. On the contrary, local magnetic moment is not exhibited by the armchair edges.

The created energy band gap enables such periodic arrays of triangular antidot lattices to be used as magnetic semiconductors. Moreover, since the energy band gap is dependent on the electron spins in the material, magnetic antidot lattices are perfectly suited for spintronic applications.