Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 19: Transport: Topological Insulators 2 (jointly with TT, MA)

HL 19.6: Talk

Monday, March 26, 2012, 16:15–16:30, H 3005

Majorana fermions in strongly interacting helical liquids — •Eran Sela, Achim Rosch, and Alexander Altland — Koeln university, Germany

Majorana fermions were proposed to occur at edges and interfaces of gapped one-dimensional systems where phases with different topological character meet due to an interplay of spin-orbit coupling, proximity-induced superconductivity and external magnetic fields. Here we investigate the effect of strong particle interactions and show that a helical liquid offers a mechanism that protects the very existence of Majorana edge states: whereas moderate interactions close the proximity gap that supports the edge states, in helical liquids the gap reopens due to two-particle processes. However, gapless fermionic excitations occur at spatial proximity to the Majorana states at interfaces and may jeopardize their long-term Majorana coherence.