Andreev Reflection in the Quantum Hall Regime at an Al/InAs Junction on a Cleaved Edge
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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866909381780570112 |
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| author | Akiho, Takafumi Irie, Hiroshi Nakazawa, Yusuke Sasaki, Satoshi Kumada, Norio Muraki, Koji |
| author_facet | Akiho, Takafumi Irie, Hiroshi Nakazawa, Yusuke Sasaki, Satoshi Kumada, Norio Muraki, Koji |
| contents | We have fabricated a superconductor/semiconductor (S/Sm) junction composed of Al and InAs using cleaved edge overgrowth. By exploiting the unique geometry with a thin Al/Pt/Al trilayer formed on the side surface of an in-situ cleaved heterostructure wafer containing an InAs quantum well, we achieve a superconducting critical field of 5 T, allowing superconductivity and quantum Hall (QH) effects to coexist down to Landau-level filling factor nu = 3. Andreev reflection at zero magnetic field shows a conductance enhancement that is limited solely by the Fermi velocity mismatch, demonstrating a virtually barrier-free, high-quality S/Sm junction. Bias spectroscopy in the QH regime reveals the opening of a superconducting gap, with the reduced downstream resistance demonstrating that the electron-hole Andreev conversion probability consistently exceeds 50%. Our results, obtained in a new experimental regime characterized by a clean edge-contacted junction with a superconducting electrode narrower than the coherence length, open new avenues for both theoretical and experimental studies of the interplay between superconductivity and QH effects and the engineering of exotic quasiparticles. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2407_21557 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Andreev Reflection in the Quantum Hall Regime at an Al/InAs Junction on a Cleaved Edge Akiho, Takafumi Irie, Hiroshi Nakazawa, Yusuke Sasaki, Satoshi Kumada, Norio Muraki, Koji Mesoscale and Nanoscale Physics We have fabricated a superconductor/semiconductor (S/Sm) junction composed of Al and InAs using cleaved edge overgrowth. By exploiting the unique geometry with a thin Al/Pt/Al trilayer formed on the side surface of an in-situ cleaved heterostructure wafer containing an InAs quantum well, we achieve a superconducting critical field of 5 T, allowing superconductivity and quantum Hall (QH) effects to coexist down to Landau-level filling factor nu = 3. Andreev reflection at zero magnetic field shows a conductance enhancement that is limited solely by the Fermi velocity mismatch, demonstrating a virtually barrier-free, high-quality S/Sm junction. Bias spectroscopy in the QH regime reveals the opening of a superconducting gap, with the reduced downstream resistance demonstrating that the electron-hole Andreev conversion probability consistently exceeds 50%. Our results, obtained in a new experimental regime characterized by a clean edge-contacted junction with a superconducting electrode narrower than the coherence length, open new avenues for both theoretical and experimental studies of the interplay between superconductivity and QH effects and the engineering of exotic quasiparticles. |
| title | Andreev Reflection in the Quantum Hall Regime at an Al/InAs Junction on a Cleaved Edge |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2407.21557 |