Banerjee, A and Sundaresh, A and Ganesan, R and Kumar, PSA (2018) Signatures of Topological Superconductivity in Bulk-Insulating Topological Insulator BiSbTe 1.25 Se 1.75 in Proximity with Superconducting NbSe 2. 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 NbSe 2 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, and 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 |
|---|---|
| Publication: | ACS Nano |
| Publisher: | American Chemical Society |
| Additional Information: | The copyright for this article belongs to the American Chemical Society. |
| Keywords: | Antimony compounds; Bismuth compounds; Electric insulators; Insulation; Locks (fasteners); Niobium compounds; Seismic waves; Selenium compounds; Shear waves; Superconducting materials; Surface states; Tellurium compounds; Van der Waals forces, 2D superconductors; Majorana; Proximity effects; Topological insulators; Van der waals, Topology |
| Department/Centre: | Division of Physical & Mathematical Sciences > Physics |
| Date Deposited: | 05 Aug 2022 06:35 |
| Last Modified: | 05 Aug 2022 06:35 |
| URI: | https://eprints.iisc.ac.in/id/eprint/75262 |
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