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Abstract The interface between 2D topological Dirac states and ans‐wave superconductor is expected to support Majorana‐bound states (MBS) that can be used for quantum computing applications. Realizing these novel states of matter and their applications requires control over superconductivity and spin‐orbit coupling to achieve spin‐momentum‐locked topological interface states (TIS) which are simultaneously superconducting. While signatures of MBS have been observed in the magnetic vortex cores of bulk FeTe0.55Se0.45, inhomogeneity and disorder from doping make these signatures unclear and inconsistent between vortices. Here superconductivity is reported in monolayer (ML) FeTe1–ySey(Fe(Te,Se)) grown on Bi2Te3by molecular beam epitaxy (MBE). Spin and angle‐resolved photoemission spectroscopy (SARPES) directly resolve the interfacial spin and electronic structure of Fe(Te,Se)/Bi2Te3heterostructures. Fory = 0.25, the Fe(Te,Se) electronic structure is found to overlap with the Bi2Te3TIS and the desired spin‐momentum locking is not observed. In contrast, fory = 0.1, reduced inhomogeneity measured by scanning tunneling microscopy (STM) and a smaller Fe(Te,Se) Fermi surface with clear spin‐momentum locking in the topological states are found. Hence, it is demonstrated that the Fe(Te,Se)/Bi2Te3system is a highly tunable platform for realizing MBS where reduced doping can improve characteristics important for Majorana interrogation and potential applications.
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Spin-selective tunneling from nanowires of the candidate topological Kondo insulator SmB 6
Incorporating relativistic physics into quantum tunneling can lead to exotic behavior such as perfect transmission through Klein tunneling. Here, we probed the tunneling properties of spin-momentum-locked relativistic fermions by designing and implementing a tunneling geometry that uses nanowires of the topological Kondo insulator candidate samarium hexaboride. The nanowires are attached to the end of scanning tunneling microscope tips and used to image the bicollinear stripe spin order in the antiferromagnet Fe1.03Te with a Neel temperature of about 50 kelvin. The antiferromagnetic stripes become invisible above 10 kelvin concomitant with the suppression of the topological surface states in the tip. We further demonstrate that the direction of spin polarization is tied to the tunneling direction. Our technique establishes samarium hexaboride nanowires as ideal conduits for spin-polarized currents.
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- Award ID(s):
- 2003784
- PAR ID:
- 10501678
- Editor(s):
- Jelena Stajic
- Publisher / Repository:
- AAAS
- Date Published:
- Journal Name:
- Science
- Volume:
- 377
- Issue:
- 6611
- ISSN:
- 0036-8075
- Page Range / eLocation ID:
- 1218 to 1222
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1126/science.abj8765
