Closing of the Induced Gap in a Hybrid Superconductor-Semiconductor Nanowire
| Autor: | Charles Marcus, Esteban Martínez, A. Pöschl, Michael J. Manfra, Gerbold Menard, Andrew Higginbotham, Lucas Casparis, Geoffrey C. Gardner, Sergei Gronin, Denise Puglia, Ray Kallaher |
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| Rok vydání: | 2020 |
| Předmět: |
Superconductivity
Physics Quantum phase transition Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics business.industry Nanowire Conductance FOS: Physical sciences 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Semiconductor 0103 physical sciences Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 010306 general physics 0210 nano-technology Spurious relationship business Excitation |
| Zdroj: | Puglia, D, Martinez, E A, Menard, G C, Poschl, A, Gronin, S, Gardner, G C, Kallaher, R, Manfra, M J, Marcus, C M, Higginbotham, A P & Casparis, L 2021, ' Closing of the induced gap in a hybrid superconductor-semiconductor nanowire ', Physical Review B, vol. 103, no. 23, 235201 . https://doi.org/10.1103/PhysRevB.103.235201 |
| DOI: | 10.48550/arxiv.2006.01275 |
| Popis: | Hybrid superconductor-semiconductor nanowires are predicted to undergo a field-induced phase transition from a trivial to a topological superconductor, marked by the closure and re-opening of the excitation gap, followed by the emergence of Majorana bound states at the nanowire ends. Many local density-of-states measurements have reported signatures of the topological phase, however this interpretation has been challenged by alternative explanations. Here, by measuring nonlocal conductance, we identify the closure of the excitation gap in the bulk of the semiconductor before the emergence of zero-bias peaks. This observation is inconsistent with scenarios where zero-bias peaks occur due to end-states with a trivially gapped bulk, which have been extensively considered in the theoretical and experimental literature. We observe that after the gap closes, nonlocal signals fluctuate strongly and persist irrespective of the presence of local-conductance zero-bias peaks. Thus, our observations are also incompatible with a simple picture of clean topological superconductivity. This work presents a new experimental approach for probing the spatial extent of states in Majorana wires, and reveals the presence of a regime with a continuum of spatially extended states and uncorrelated zero-bias peaks. |
| Databáze: | OpenAIRE |
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