Regensburg 2013 – scientific programme

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MA: Fachverband Magnetismus

MA 30: Focused Session: Majorana Fermions in Condensed Matter (jointly with DS, HL, MA, and O)

MA 30.4: Topical Talk

Wednesday, March 13, 2013, 16:45–17:15, H20

Majorana Fermions in Disordered Quantum Wires — •Alexander Altland — Institute for Theoretical Physics, Zülpicher Str. 77, 50937 Köln

Proximity coupled spin-orbit quantum wires have recently been shown to support midgap Majorana states at critical points. We show that in the presence of disorder these systems are prone to the buildup of a second bandcenter anomaly, which is of different physical origin but shares key characteristics with the Majorana state: it is narrow in width, insensitive to magnetic fields, carries unit spectral weight, and is rigidly tied to the band center. Depending on the parity of the number of subgap quasiparticle states, a Majorana mode does or does not coexist with the impurity generated peak. The strong 'entanglement' between the two phenomena may hinder an unambiguous detection of the Majorana by spectroscopic techniques.