Spectroscopic Visualization of a Robust Electronic Response of Semiconducting Nanowires to Deposition of Superconducting Islands
Following significant progress in the visualization and characterization of Majorana end modes in hybrid systems of semiconducting nanowires and superconducting islands, much attention is devoted to the investigation of the electronic structure at the buried interface between the semiconductor and t...
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American Physical Society
2020
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oai:doaj.org-article:c07f848997724013846ebec8cf3470642021-12-02T11:26:33ZSpectroscopic Visualization of a Robust Electronic Response of Semiconducting Nanowires to Deposition of Superconducting Islands10.1103/PhysRevX.10.0110022160-3308https://doaj.org/article/c07f848997724013846ebec8cf3470642020-01-01T00:00:00Zhttp://doi.org/10.1103/PhysRevX.10.011002http://doi.org/10.1103/PhysRevX.10.011002https://doaj.org/toc/2160-3308Following significant progress in the visualization and characterization of Majorana end modes in hybrid systems of semiconducting nanowires and superconducting islands, much attention is devoted to the investigation of the electronic structure at the buried interface between the semiconductor and the superconductor. The properties of that interface and the structure of the electronic wave functions that occupy it determine the functionality and the topological nature of the superconducting state induced therein. Here we study this buried interface by performing spectroscopic mappings of superconducting aluminum islands epitaxially grown in situ on indium arsenide nanowires. We find unexpected robustness of the hybrid system as the direct contact with the aluminum islands does not lead to any change in the chemical potential of the nanowires, nor does it induce a significant band bending in their vicinity. We attribute this to the presence of surface states bound to the facets of the nanowire. Such surface states, which are present also in bare nanowires prior to aluminum deposition, pin the Fermi level, thus rendering the nanowires resilient to surface perturbations. The aluminum islands further display Coulomb blockade gaps and peaks that signify the formation of a resistive tunneling barrier at the InAs-Al interface. The extracted interface resistivity, ρ≈1.3×10^{-6} Ω cm^{2}, will allow us to proximity induce superconductivity with negligible Coulomb blockade effects by islands with interface area as small as 0.01 μm^{2}. At low energies we identify a potential energy barrier that further suppresses the transmittance through the interface. A corresponding barrier exists in bare semiconductors between surface states and the accumulation layer, induced to maintain charge neutrality. Our observations elucidate the delicate interplay between the resistive nature of the InAs-Al interface and the ability to proximitize superconductivity and tune the chemical potential in semiconductor-superconductor hybrid nanowires.Jonathan ReinerAbhay Kumar NayakAmit TulchinskyAviram SteinbokTom KorenNoam MoraliRajib BatabyalJung-Hyun KangNurit AvrahamYuval OregHadas ShtrikmanHaim BeidenkopfAmerican Physical SocietyarticlePhysicsQC1-999ENPhysical Review X, Vol 10, Iss 1, p 011002 (2020) |
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| topic |
Physics QC1-999 |
| spellingShingle |
Physics QC1-999 Jonathan Reiner Abhay Kumar Nayak Amit Tulchinsky Aviram Steinbok Tom Koren Noam Morali Rajib Batabyal Jung-Hyun Kang Nurit Avraham Yuval Oreg Hadas Shtrikman Haim Beidenkopf Spectroscopic Visualization of a Robust Electronic Response of Semiconducting Nanowires to Deposition of Superconducting Islands |
| description |
Following significant progress in the visualization and characterization of Majorana end modes in hybrid systems of semiconducting nanowires and superconducting islands, much attention is devoted to the investigation of the electronic structure at the buried interface between the semiconductor and the superconductor. The properties of that interface and the structure of the electronic wave functions that occupy it determine the functionality and the topological nature of the superconducting state induced therein. Here we study this buried interface by performing spectroscopic mappings of superconducting aluminum islands epitaxially grown in situ on indium arsenide nanowires. We find unexpected robustness of the hybrid system as the direct contact with the aluminum islands does not lead to any change in the chemical potential of the nanowires, nor does it induce a significant band bending in their vicinity. We attribute this to the presence of surface states bound to the facets of the nanowire. Such surface states, which are present also in bare nanowires prior to aluminum deposition, pin the Fermi level, thus rendering the nanowires resilient to surface perturbations. The aluminum islands further display Coulomb blockade gaps and peaks that signify the formation of a resistive tunneling barrier at the InAs-Al interface. The extracted interface resistivity, ρ≈1.3×10^{-6} Ω cm^{2}, will allow us to proximity induce superconductivity with negligible Coulomb blockade effects by islands with interface area as small as 0.01 μm^{2}. At low energies we identify a potential energy barrier that further suppresses the transmittance through the interface. A corresponding barrier exists in bare semiconductors between surface states and the accumulation layer, induced to maintain charge neutrality. Our observations elucidate the delicate interplay between the resistive nature of the InAs-Al interface and the ability to proximitize superconductivity and tune the chemical potential in semiconductor-superconductor hybrid nanowires. |
| format |
article |
| author |
Jonathan Reiner Abhay Kumar Nayak Amit Tulchinsky Aviram Steinbok Tom Koren Noam Morali Rajib Batabyal Jung-Hyun Kang Nurit Avraham Yuval Oreg Hadas Shtrikman Haim Beidenkopf |
| author_facet |
Jonathan Reiner Abhay Kumar Nayak Amit Tulchinsky Aviram Steinbok Tom Koren Noam Morali Rajib Batabyal Jung-Hyun Kang Nurit Avraham Yuval Oreg Hadas Shtrikman Haim Beidenkopf |
| author_sort |
Jonathan Reiner |
| title |
Spectroscopic Visualization of a Robust Electronic Response of Semiconducting Nanowires to Deposition of Superconducting Islands |
| title_short |
Spectroscopic Visualization of a Robust Electronic Response of Semiconducting Nanowires to Deposition of Superconducting Islands |
| title_full |
Spectroscopic Visualization of a Robust Electronic Response of Semiconducting Nanowires to Deposition of Superconducting Islands |
| title_fullStr |
Spectroscopic Visualization of a Robust Electronic Response of Semiconducting Nanowires to Deposition of Superconducting Islands |
| title_full_unstemmed |
Spectroscopic Visualization of a Robust Electronic Response of Semiconducting Nanowires to Deposition of Superconducting Islands |
| title_sort |
spectroscopic visualization of a robust electronic response of semiconducting nanowires to deposition of superconducting islands |
| publisher |
American Physical Society |
| publishDate |
2020 |
| url |
https://doaj.org/article/c07f848997724013846ebec8cf347064 |
| work_keys_str_mv |
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1718395962010894336 |