Speaker
Carlo Beenakker
(Leiden University)
Description
Vortices in two-dimensional superconductors with broken
time-reversal and spin-rotation symmetry can bind states at
zero excitation energy. These socalled Majorana bound
states transform a thermal insulator into a thermal metal
and may be used to encode topologically protected qubits.
We identify an alternative mechanism for the formation of
Majorana bound states, akin to the way in which Shockley
states are formed on metal surfaces: An atomic-scale
electrostatic line defect can have a pair of Majorana bound
states at the end points. The Shockley mechanism explains
the appearance of a thermal metal in vortex-free lattice
models of chiral p-wave superconductors and (unlike the
vortex mechanism) is also operative in the topologically
trivial phase.
