Physics

Electron

Nanotechnology

Mathematics

Open shell

Magnetic moment

Scanning tunneling microscope

Excited state

Atomic physics

Zigzag

Materials science

Magnetism

Geometry

Condensed matter physics

Spins

Graphene

Singlet state

Spin states

Molecular physics

Spin (aerodynamics)

Quantum mechanics

Ground state

Thermodynamics

Nature Communications

Predictions state that graphene can spontaneously develop magnetism from the Coulomb repulsion of its $\pi$-electrons, but its experimental verification has been a challenge. Here, we report on the observation and manipulation of individual magnetic moments localized in graphene nanostructures on a Au(111) surface. Using scanning tunneling spectroscopy, we detected the presence of single electron spins localized around certain zigzag sites of the carbon backbone via the Kondo effect. Two near-by spins were found coupled into a singlet ground state, and the strength of their exchange interaction was measured via singlet-triplet inelastic tunnel electron excitations. Theoretical simulations demonstrate that electron correlations result in spin-polarized radical states with the experimentally observed spatial distributions. Hydrogen atoms bound to these radical sites quench their magnetic moment, permitting us to switch the spin of the nanostructure using the tip of the microscope.

Single spin localization and manipulation in graphene open-shell nanostructures