Accessing Quantum Magnetism at the Atomic Scale
In the last few decades, there have been dramatic advances in accessing and manipulating individual quantum spins. This has opened the possibility of fabricating a broad range of model systems with a finite number of spins that are predicted to exhibit novel quantum phenomena and that may be exploited for future technological applications. In many situations, coupling such systems to the external environment has detrimental consequences, such as decreasing the lifetime of spin excitations. However, such external coupling to the local environment can also create new opportunities for manipulating and controlling the magnetic properties and interactions that are manifested. Using scanning tunneling microscopy (STM), we study the effects of interactions with the local environment on individual magnetic atoms and molecules that are separated from an underlying metallic substrate by an atomically thin insulating layer. Spatially resolved STM-based spectroscopy enables us to measure the local density of states and the low energy spin-excitation spectra of the individual magnetic nanostructures. This can be used to determine the strength of the interactions between the spins and the local environment as well as the novel changes in state that these interactions can cause. The result is an atomic-scale toolbox for engineering magnetic structures for quantum science and technology atom by atom.