Banerjee, Abhishek and Sundaresh, Ananthesh and Ganesan, Rajamanickam and Kumar, PS Anil (2018) Signatures of Topological Superconductivity in Bulk-Insulating Topological Insulator BiSbTe1.25Se1.75 in Proximity with Superconducting NbSe2. In: ACS NANO, 12 (12). pp. 12665-12672.
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Abstract
The combination of superconductivity and spin-momentum locking at the interface between an s-wave superconductor and a three-dimensional topological insulator (3D-TI) is predicted to generate exotic p-wave topological superconducting phases that can host Majorana Fermions. However, large bulk conductivities of previously investigated 3D-TI samples and Fermi level mismatches between 3D bulk superconductors and 2D topological surface states have thwarted significant progress. Here, we employ bulk-insulating topological insulators in proximity with two-dimensional superconductor NbSe2 assembled via van der Waals epitaxy. Experimentally measured differential conductance yields unusual features including a double-gap spectrum, an intrinsic asymmetry that vanishes with small in-plane magnetic fields, differential conductance ripples at biases significantly larger than the superconducting gap. We explain our results on the basis of proximity-induced superconductivity of topological surface states, while also considering possibilities of topologically trivial superconductivity arising from Rashba-type surface states. Our work demonstrates the possibility of obtaining p-wave superconductors by proximity effects on bulk-insulating TIs.
Item Type: | Journal Article |
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Publication: | ACS NANO |
Publisher: | AMER CHEMICAL SOC |
Additional Information: | Copyright of this article belongs to AMER CHEMICAL SOC |
Keywords: | topological superconductivity; Majorana Fermions; proximity effect; topological insulator; 2D superconductor; van der Waals heterostructure |
Department/Centre: | Division of Physical & Mathematical Sciences > Physics |
Date Deposited: | 28 Jan 2019 09:27 |
Last Modified: | 28 Jan 2019 09:27 |
URI: | http://eprints.iisc.ac.in/id/eprint/61491 |
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