We propose a way to generate a one-dimensional topological superconductor
from a monolayer of a transition metal dichalcogenide coupled to a
Bernal-stacked bilayer of graphene under a displacement field. With proper
gating, this structure may be tuned to form three parallel pads of
superconductors creating two planar Josephson junctions in series, in which
normal regions separate the superconductors. Two characteristics of the system
which are essential for our discussion are spin orbit coupling induced by the
transition metal dichalcogenides and the variation of the Fermi velocities
along the Fermi surface. We demonstrate that these two characteristics lead to
one-dimensional topological superconductivity occupying large parts in the
parameter space defined by the two phase differences across the two junctions
and the relative angle between the junctions and the lattice. An angle-shaped
device in which this angle varies in space, combined with proper phase tuning,
can lead to the formation of domain walls between topological and trivial
phases, supporting a zero-energy Majorana mode, within the bulk of carefully
designed devices. We derive the spectrum of the Andreev bound states and show
that Ising spin-orbit coupling leaves the topological superconductor gapless,
and the Rashba spin-orbit coupling opens a gap in its spectrum. Our analysis
shows that the transition to a gapped topological state is a result of the band
inversion of Andreev states.

Este artículo explora los viajes en el tiempo y sus implicaciones.

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