Simple Quantum Operations with Molecular Magnets on Surfaces

The aim of this project is to deposit spin-carrying metal-organic molecules in well defined geometries onto surfaces and to determine and manipulate their magnetic state in a controlled fashion. This way, simple quantum operations should be realized based on individual magnetic molecules. Two complementary approaches will be taken. On the one hand, 3d transition metal ions surrounded by organic ligands will be used, in which the ligand field drives a spin crossover. Using the tip of a scanning tunneling microscope (STM) or photons, the molecules should be switches between the high- and low-spin state. The high spin state could lead to a many body ground state of the local molecular spin and the conduction electrons, i.e. to a Kondo state. On the other hand, strongly localized spins of 4f-ions of metal organic molecules will be used. These are not expected to hybridize that much with the conduction electrons and in combination with the high expected magnetic anisotropy, long lived spin states are excepted. The spins can be excited with STM and the spin lifetime can be extracted. Thus, in both approaches, single spins will be investigated to realize simple quantum operations.