Thermoelectric signatures of a Majorana bound state coupled to a quantum dot

Abstract

We theoretically investigate the possibility to use thermolectric measurements to detect Majorana bound states and to investigate their coupling to a dissipative environment. The particle-hole symmetry of Majorana states would normally lead to a vanishing Seebeck coefficient, i.e. a vanishing open-circuit voltage resulting from a temperature gradient. We discuss how coupling to a quantum dot with a gate-controlled energy level breaks particle-hole symmetry in a tunable manner. The resulting gate-dependent Seebeck coefficient provides a new way to evidence the existence of Majorana states, which can be combined with conventional tunnel spectroscopy in the same setup. Furthermore, the thermoelectric properties rely on the ability of the quantum dot-Majorana system to sense the temperature of the bulk superconductor and can be used to extract information about the dissipative decay of Majorana states, which is crucial for quantum information applications. © 2014 IOP Publishing and Deutsche Physikalische Gesellschaft.