Adsorption analysis of Fe-ZQ on Cu(110) and V-ZQ on Au(110) using density functional theory

Abstract

This study investigates the behavior of polymers composed of transition metals (TM) and zwitterionic quinone (ZQ) molecules in two-dimensional (2D) configurations adsorbed on metallic substrates. We focus on the electronic and magnetic properties of these polymer chains, specifically those based on vanadium (V) and iron (Fe) atoms combined with zwitterionic quinone, when placed on Au(110) and Cu(110) surfaces, respectively. Our investigation employs SGGA + U calculations to provide detailed insights into the adsorption preferences and magnetic characteristics of these polymers. We find that V-ZQ polymers exhibit a preference for adsorption at the short-bridge site on the Au(110) surface. At this site, the vanadium atom displays a magnetic moment of approximately 3 ${\mu }_B$, indicating significant magnetic behavior. In contrast, Fe-ZQ polymers are most favorably adsorbed at the hollow (H) site on the Cu(110) surface, with a substantial adsorption energy of E_ads = −1.51 eV. The total magnetic moment per iron atom in these Fe-ZQ polymers is calculated to be 2 ${\mu }_B$, which corresponds to a spin state of S = 1. An important charge transfer between substrate and monolayer is calculated, especially for the Cu substrate which influences, however, the local magnetic moments in a negligible way. Magnetic moments are stable despite a remarkable charge transfer. These findings highlight the distinct adsorption behaviors and magnetic properties of V-ZQ and Fe-ZQ polymers on different metallic surfaces, contributing to our understanding of their potential applications in nanotechnology and materials science.