Berlin 2024 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 85: Topology: Majorana Physics II
TT 85.7: Vortrag
Freitag, 22. März 2024, 11:15–11:30, H 3005
Exploration of topological states and multiple gaps in MgB2 superconductors — •Nora Kucska1, Andras Laszloffy1, Laszlo Szunyogh2, and Balazs Ujfalussy1 — 1HUN-REN Wigner Research Centre for Physics, Budapest, Hungary — 2Budapest University of Technology and Economics, Budapest, Hungary
Unfortunately, most known topological superconductors possess low transition temperatures, impeding the experimental observation of Majorana fermions. MgB2, a widely recognized high-temperature superconductor would consequently be an ideal subject to study due to the suspected topological properties of its band structure. This gives light to its intriguing quantum phase characterized by protected gapless surface/edge states within a bulk superconducting gap, possibly hosting Majorana fermions.
Using fully relativistic first-principles calculations, a Dirac-nodal line structure is investigated through the bulk and surface band structure of MgB2. Adding magnetic impurities to the surface, the interaction between the topological system with the impurities is explored.
MgB2 is also known for having multiple gaps in the superconducting state. Numerous experimental and theoretical studies find either one or two distinct gaps in the density of states, while a third gap was found in thin films of MgB2 and by theoretical non-relativistic ab initio calculations. The multiple gap structure of MgB2 was analyzed giving more insights on the topic. We study the so-called Yu-Shiba-Rusinov states in the context of this multi gapped superconductor.
Keywords: first principle calculations; topological superconductors; multiple gaps; magnetic impurities