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Physics Colloquium

Magnetic conducting two-dimensional electrons on the surface of a three-dimensional insulator

Majorana fermions, fermions which are their own antiparticle, are predicted to appear in material systems known as topological superconductors (TSC). It is possible for these exotic fermions to exist in TSCs because they are topologically protected, meaning that perturbations away from ideal conditions will not destroy them. One proposal to achieve TSC is to use the magnetic twodimensional electrons predicted to appear on the surface of sodium cobaltate. These electrons are "perfectly" magnetic in that they are completely spinpolarized, also known as being half-metallic. Using scanning tunneling microscopy (STM), we characterize these half-metallic electrons and examine how they evolve in energy over atomic length scales. Additionally, I will discuss how STM can be used to induce topological superconductivity into this material.