Coherent dynamics of atomic spins on a surface
L.M. Veldman (TU Delft - QN/Otte Lab)
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Abstract
This thesis presents experiments on the free, coherent spin dynamics ofmagnetic nanostructures built out of individual titanium atoms adsorbed on bilayer MgOislands grown on a Ag(100) crystal inside a scanning tunneling microscope (STM).We use the exchange field of the spin-polarized probe tip to tune the eigenstates of the magnetic structures to superpositions of the Zeeman product states. These superpositions appear as avoided level crossings of the eigenenergies as a function of tip-atom distance and are detected through electron spin resonance (ESR) measurements. Subsequently,we put the STMtip at the position where we detect an avoided crossing and we perform a DC pump-probe experiment. Here, the pump pulse causes a single spin flip on the atom under state tip which is then allowed to evolve freely for some time t until it is measured by the subsequent probe pulse. By varying the time t between pump and probe over many experiments, we are able to trace out the evolution of the spin under the tip with nanosecond time resolution....