Substitutional 4d and 5d Impurities in Graphene

TL;DR

This paper investigates the structural and electronic effects of doping graphene with 4d and 5d transition metal impurities, revealing trends in binding, magnetic moments, and hybridization that differ from 3d elements, with implications for magnetic properties.

Contribution

It provides a detailed comparison of 4d and 5d impurity effects in graphene, highlighting unique magnetic and electronic behaviors not previously characterized.

Findings

4d and 5d impurities show similar trends in binding energies and distances.

Magnetic moments are reduced for certain elements like technetium and rhenium.

High hybridization reduces spin splitting, affecting magnetic properties.

Abstract

We describe the structural and electronic properties of graphene doped with substitutional impurities of 4d and 5d transition metals. The binding energy and distances for 4d and 5d metals in graphene show similar trends for the later groups in the periodic table, which is also well-known characteristic of 3d elements. However, along earlier groups the 4d impurities in graphene show very similar binding energies, distances and magnetic moments to 5d ones, which can be related to the influence of the 4d and 5d lanthanide contraction. Surprisingly, within the manganese group, the total magnetic moment of 3$\mu_{B}$ for manganese is reduced to 1$\mu_{B}$ for technetium and rhenium. We find that with compared with 3d elements, the larger size of the 4d and 5d elements causes a high degree hybridization with the neighbouring carbon atoms, reducing spin splitting in the d levels. It seems that the magnetic adjustment of graphene could be significantly different is 4d or 5d impurities are used instead of 3d impurities.