TY - JOUR
T1 - Semiconductor-ferromagnet-superconductor planar heterostructures for 1D topological superconductivity
AU - Escribano, Samuel D.
AU - Maiani, Andrea
AU - Leijnse, Martin
AU - Flensberg, Karsten
AU - Oreg, Yuval
AU - Levy Yeyati, Alfredo
AU - Prada, Elsa
AU - Souto, Ruben Seoane
PY - 2022/8/18
Y1 - 2022/8/18
N2 - Hybrid structures of semiconducting (SM) nanowires, epitaxially grown superconductors (SC), and ferromagnetic-insulator (FI) layers have been explored experimentally and theoretically as alternative platforms for topological superconductivity at zero magnetic field. Here, we analyze a tripartite SM/FI/SC heterostructure but realized in a planar stacking geometry, where the thin FI layer acts as a spin-polarized barrier between the SM and the SC. We optimize the system's geometrical parameters using microscopic simulations, finding the range of FI thicknesses for which the hybrid system can be tuned into the topological regime. Within this range, and thanks to the vertical confinement provided by the stacking geometry, trivial and topological phases alternate regularly as the external gate is varied, displaying a hard topological gap that can reach half of the SC one. This is a significant improvement compared to setups using hexagonal nanowires, which show erratic topological regions with typically smaller and softer gaps. Our proposal provides a magnetic field-free planar design for quasi-one-dimensional topological superconductivity with attractive properties for experimental control and scalability.
AB - Hybrid structures of semiconducting (SM) nanowires, epitaxially grown superconductors (SC), and ferromagnetic-insulator (FI) layers have been explored experimentally and theoretically as alternative platforms for topological superconductivity at zero magnetic field. Here, we analyze a tripartite SM/FI/SC heterostructure but realized in a planar stacking geometry, where the thin FI layer acts as a spin-polarized barrier between the SM and the SC. We optimize the system's geometrical parameters using microscopic simulations, finding the range of FI thicknesses for which the hybrid system can be tuned into the topological regime. Within this range, and thanks to the vertical confinement provided by the stacking geometry, trivial and topological phases alternate regularly as the external gate is varied, displaying a hard topological gap that can reach half of the SC one. This is a significant improvement compared to setups using hexagonal nanowires, which show erratic topological regions with typically smaller and softer gaps. Our proposal provides a magnetic field-free planar design for quasi-one-dimensional topological superconductivity with attractive properties for experimental control and scalability.
KW - ZERO-BIAS PEAKS
KW - MAJORANA
U2 - 10.1038/s41535-022-00489-9
DO - 10.1038/s41535-022-00489-9
M3 - Journal article
VL - 7
JO - npj Quantum Materials
JF - npj Quantum Materials
SN - 2397-4648
IS - 1
M1 - 81
ER -