Gas adsorption effects on electronic and magnetic properties of triangular graphene antidot lattices

TL;DR

This study investigates how small and large molecule adsorption affects the electronic and magnetic properties of triangular graphene antidot lattices, revealing potential for sensor and magnetic device applications.

Contribution

It provides first-principles insights into molecule-specific effects on GALs, highlighting NO$_{2}$'s role in inducing magnetism and half-metallicity.

Findings

NO$_{2}$ chemisorption alters energy gap to half-metallic state

Tetracyanoquinodimethane molecules induce flat bands near Fermi level

NO$_{2}$ molecules produce the highest magnetic moment

Abstract

The adsorption effects of small molecules (H$_{2}$O, CO, NH$_{3}$, NO$_{2}$) and large molecules (Tetracyanoquinodimethane (TCNQ) and Tetrafluoro-tetracyanoquinodimethane (F4TCNQ)) on electronic and magnetic properties of two triangular graphene antidot lattices (GALs), $[10,3,6]_{RTA}$ and $[10, 5]_{ETA}$, are investigated by means of first-principles calculations. We find that CO, NO$_{2}$, TCNQ, and F4TCNQ molecules are chemisorbed by both antidots, whereas NH$_{3}$ is physisorbed (chemisorbed) by $[10, 5]_{ETA}$ ($[10,3,6]_{RTA}$) structure. H$_{2}$O, CO, NH$_{3}$ molecules reveal no significant effect on electronic and magnetic properties of these antidot structures. The adsorbed NO$_{2}$ molecules affect the energy gap of GALs by changing their electronic structure from semiconducting to half-metal nature. This suggests that both GALs can act as efficient NO$_{2}$ sensors. The adsorption of TCNQ and F4TCNQ molecules on GALs induces flat bands in the vicinity of the Fermi energy and also turn the electronic structure of antidot lattices to half-metallicity. Among the small and large molecules, NO$_{2}$ molecules induce the most total magnetic moment, paving the way to make magnetic GAL-based devices.