Quantized conductance at the Majorana phase transition in a disordered superconducting wire

• Published in: Physical review letters Vol. 106; no. 5; p. 057001
• Main Authors: Akhmerov, A R, Dahlhaus, J P, Hassler, F, Wimmer, M, Beenakker, C W J
• Format: Journal Article
• Language: English
• Published: United States 31.01.2011
• ISSN: 1079-7114
• DOI: 10.1103/physrevlett.106.057001

Superconducting wires without time-reversal and spin-rotation symmetries can be driven into a topological phase that supports Majorana bound states. Direct detection of these zero-energy states is complicated by the proliferation of low-lying excitations in a disordered multimode wire. We show that the phase transition itself is signaled by a quantized thermal conductance and electrical shot noise power, irrespective of the degree of disorder. In a ring geometry, the phase transition is signaled by a period doubling of the magnetoconductance oscillations. These signatures directly follow from the identification of the sign of the determinant of the reflection matrix as a topological quantum number.