TY - JOUR

T1 - Zero-bias peaks at zero magnetic field in ferromagnetic hybrid nanowires

AU - Vaitiekenas, S.

AU - Liu, Y.

AU - Krogstrup, P.

AU - Marcus, C. M.

PY - 2020/9/22

Y1 - 2020/9/22

N2 - Hybrid quantum materials allow for quantum phases that otherwise do not exist in nature(1,2). For example, a one-dimensional topological superconductor with Majorana states bound to its ends can be realized by coupling a semiconductor nanowire to a superconductor in the presence of a strong magnetic field(3-5). However, the applied magnetic fields are detrimental to superconductivity, and constrain device layout, components, materials, fabrication and operation(6). Early on, an alternative source of Zeeman coupling that circumvents these constraints-using a ferromagnetic insulator instead of an applied field-was proposed theoretically(7). Here, we report transport measurements in hybrid nanowires using epitaxial layers of superconducting Al and the ferromagnetic insulator EuS on semiconducting InAs nanowires. We infer a remanent effective Zeeman field exceeding 1 T and observe stable zero-bias conductance peaks in bias spectroscopy at zero applied field, consistent with topological superconductivity. Hysteretic spectral features in applied magnetic field support this picture.By incorporating a ferromagnetic layer in their superconductor-semiconductor nanowire hybrid device, Vaitiekenas et al. show that zero-bias peaks-potential Majorana bound states-can be induced without an external magnetic field.

AB - Hybrid quantum materials allow for quantum phases that otherwise do not exist in nature(1,2). For example, a one-dimensional topological superconductor with Majorana states bound to its ends can be realized by coupling a semiconductor nanowire to a superconductor in the presence of a strong magnetic field(3-5). However, the applied magnetic fields are detrimental to superconductivity, and constrain device layout, components, materials, fabrication and operation(6). Early on, an alternative source of Zeeman coupling that circumvents these constraints-using a ferromagnetic insulator instead of an applied field-was proposed theoretically(7). Here, we report transport measurements in hybrid nanowires using epitaxial layers of superconducting Al and the ferromagnetic insulator EuS on semiconducting InAs nanowires. We infer a remanent effective Zeeman field exceeding 1 T and observe stable zero-bias conductance peaks in bias spectroscopy at zero applied field, consistent with topological superconductivity. Hysteretic spectral features in applied magnetic field support this picture.By incorporating a ferromagnetic layer in their superconductor-semiconductor nanowire hybrid device, Vaitiekenas et al. show that zero-bias peaks-potential Majorana bound states-can be induced without an external magnetic field.

KW - SUPERCONDUCTOR

KW - STATES

U2 - 10.1038/s41567-020-1017-3

DO - 10.1038/s41567-020-1017-3

M3 - Journal article

JO - Nature Physics

JF - Nature Physics

SN - 1745-2473

ER -