Doping transition-metal atoms in graphene for atomic-scale tailoring of electronic, magnetic, and quantum topological properties

TL;DR

This paper demonstrates a method to precisely dope graphene with transition-metal atoms using an electron beam, enabling atomic-scale control over its electronic, magnetic, and topological properties, supported by theoretical calculations.

Contribution

It introduces a technique combining electron beam manipulation and first-principles calculations to controllably dope graphene with transition metals at the atomic scale.

Findings

Electron beam can selectively insert transition metals into graphene.

Doped structures exhibit unique magnetic and electronic properties.

Theoretical analysis reveals energetics and potential topological features.

Abstract

Atomic-scale fabrication is an outstanding challenge and overarching goal for the nanoscience community. The practical implementation of moving and fixing atoms to a structure is non-trivial considering that one must spatially address the positioning of single atoms, provide a stabilizing scaffold to hold structures in place, and understand the details of their chemical bonding. Free-standing graphene offers a simplified platform for the development of atomic-scale fabrication and the focused electron beam in a scanning transmission electron microscope can be used to locally induce defects and sculpt the graphene. In this scenario, the graphene forms the stabilizing scaffold and the experimental question is whether a range of dopant atoms can be attached and incorporated into the lattice using a single technique and, from a theoretical perspective, we would like to know which dopants will create technologically interesting properties. Here, we demonstrate that the electron beam can be used to selectively and precisely insert a variety of transition metal atoms into graphene with highly localized control over the doping locations. We use first-principles density functional theory calculations with direct observation of the created structures to reveal the energetics of incorporating metal atoms into graphene and their magnetic, electronic, and quantum topological properties.