Berlin 2018 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 32: Focus Session: Chiral Topological Superconductors and Majorana Fermions
TT 32.6: Talk
Tuesday, March 13, 2018, 12:15–12:30, H 0104
Magnetic impurities on superconducting surfaces — •Nicolas Lorente — Centro de Física de Materiales and Materials Physics Center, CSIC-EHU Donostia International Physics Center, San Sebastián, Spain
A magnetic impurity on a superconducting surface can create a bound state. The state is localized to the magnetic impurity but it extends well into the superconductor and along the surface. Its energy is within the superconductor’s gap. This state is a complex state caused by the weakening of Cooper pairs due to the magnetic exchange field produced by the impurity. If another magnetic impurity is approached, the Shiba states can start interacting. If their spins are aligned, they can form bonding and antibonding states. As the number of impurities increases forming a chain of impurities, the Shiba states also increase forming Shiba bands. Under certain conditions, some of these bands can cross the Fermi energy, closing the superconducting gap. This can give rise to changes in the topological electronic structure of the system. As a consequence, if the chain is not infinite, bound states at the edges of the chain are actually Majorana fermions. I will show model calculations analyzing the case of Cr chains on a β-Bi2Pd superconductor.