Evidence for Helical Hinge Zero Modes in an Fe-Based Superconductor.
Nano Lett
; 19(8): 4890-4896, 2019 Aug 14.
Article
en En
| MEDLINE
| ID: mdl-31268723
ABSTRACT
Combining topology and superconductivity provides a powerful tool for investigating fundamental physics as well as a route to fault-tolerant quantum computing. There is mounting evidence that the Fe-based superconductor FeTe0.55Se0.45 (FTS) may also be topologically nontrivial. Should the superconducting order be s±, then FTS could be a higher order topological superconductor with helical hinge zero modes (HHZMs). To test the presence of these modes, we have fabricated normal-metal/superconductor junctions on different surfaces via 2D atomic crystal heterostructures. As expected, junctions in contact with the hinge reveal a sharp zero bias anomaly that is absent when tunneling purely into the c-axis. Additionally, the shape and suppression with temperature are consistent with highly coherent modes along the hinge and are incongruous with other origins of zero bias anomalies. Additional measurements with soft-point contacts in bulk samples with various Fe interstitial contents demonstrate the intrinsic nature of the observed mode. Thus, we provide evidence that FTS is indeed a higher order topological superconductor.
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01-internacional
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MEDLINE
Idioma:
En
Revista:
Nano Lett
Año:
2019
Tipo del documento:
Article
País de afiliación:
Estados Unidos