Ballistic Majorana nanowire devices
Résumé
Majorana modes are zero-energy excitations of
a topological superconductor that exhibit non-
Abelian statistics
.
Following proposals for
their detection in a semiconductor nanowire cou-
pled to an s-wave superconductor
, several tun-
neling experiments reported characteristic Majo-
rana signatures
. Reducing disorder has been
a prime challenge for these experiments because
disorder can mimic the zero-energy signatures of
Majoranas
, and renders the topological prop-
erties inaccessible
. Here, we show character-
istic Majorana signatures in InSb nanowire de-
vices exhibiting clear ballistic transport proper-
ties. Application of a magnetic field and spatial
control of carrier density using local gates gen-
erates a zero bias peak that is rigid over a large
region in the parameter space of chemical poten-
tial, Zeeman energy, and tunnel barrier potential.
The reduction of disorder allows us to resolve sep-
arate regions in the parameter space with and
without a zero bias peak, indicating topologically
distinct phases. These observations are consistent
with the Majorana theory in a ballistic system
,and exclude for the first time the known alter-
native explanations that invoke disorder
or a nonuniform chemical potential