Class D spectral peak in Majorana quantum wires.
Proximity coupled spin-orbit quantum wires purportedly support midgap Majorana states at critical points. We show that, in the presence of disorder, these systems generate a second band center 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 peak. The strong "entanglement" between the two phenomena may hinder an unambiguous detection of the Majorana by spectroscopic techniques.
Institut für Theoretische Physik, Universität zu Köln, Köln 50937, Germany.
Dmitry
D
Bagrets
Alexander
A
Altland