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Iron-chalcogenide based superconductor have set a new paradigm in exploring microscopic
mechanism of superconductivity and a race to discover high-T c interfacial superconductor. It
also offer a new platform to realize pristine topological superconductivity and Majorana bound
state at relatively high temperature [1, 2].
In this talk, I will discuss our recent findings of atomic scale spin structure and
superconductivity in single layer Fe-chalcogenide (FeSe x Te 1-x ) films grown on Bi-based 3D
topological insulator, using state of art MBE-STM. At first, we show the existence of non-
collinear antiferromagnetic state in a monolayer FeTe under 2D limit, as revealed by spin-
polarized scanning tunnelling spectroscopy. A detailed investigation of the temperature,
magnetic field and spatial evolution of the electronic structure across the magnetic domains
indicates that the unit-cell of FeTe is in very close proximity to a superconducting phase
transition that coexisting with the anti-ferromagnetism [3, 4]. This will followed by discussio n
in spatial distribution of superconductivity in single layer FeSe 0.5 Te 0.5 with higher critical
temperature, which provides an ideal platform to study novel emergent phase in close
proximity to a topological insulator [5].
Finally, I will discuss our unique experimental approach towards unveiling elusive Majorana
fermion in artificially constructed one-dimensional topological superconductor in combinatio n
with large Rashba surface state and an S-wave superconductor.
References
1. G. Xu et al., Phys. Rev. Lett. 117, 047001 (2016).
2. D. Wang et al., Arxiv: 1706.06074.
3. S. Manna et al., Nature Comm. 8, 14074 (2017).
4. T. Hänke et al., Nature Comm. 8, 13939 (2017).
5. A. Kamlapure et al., Phys. Rev. B 95, 104509 (2017). |