Zero-bias conductance peak in Dirac semimetal-superconductor devices
Majorana zero modes (MZMs), fundamental building blocks for realizing topological quantum computers, can appear at the interface between a superconductor and a topological material. One of the experimental signatures that has been widely pursued to confirm the existence of MZMs is the observation of...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2020-07-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.2.032002 |
| _version_ | 1827286141658726400 |
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| author | W. Yu Rafael Haenel M. A. Rodriguez S. R. Lee F. Zhang M. Franz D. I. Pikulin W. Pan |
| author_facet | W. Yu Rafael Haenel M. A. Rodriguez S. R. Lee F. Zhang M. Franz D. I. Pikulin W. Pan |
| author_sort | W. Yu |
| collection | DOAJ |
| description | Majorana zero modes (MZMs), fundamental building blocks for realizing topological quantum computers, can appear at the interface between a superconductor and a topological material. One of the experimental signatures that has been widely pursued to confirm the existence of MZMs is the observation of a large, quantized zero-bias conductance peak (ZBCP) in the differential conductance measurements. In this Letter, we report observation of such a large ZBCP in junction structures of normal metal (titanium/gold Ti/Au)—Dirac semimetal (cadmium-arsenide Cd_{3}As_{2})—conventional superconductor (aluminum Al), with a value close to four times that of the normal state conductance. Our detailed analyses suggest that this large ZBCP is most likely not caused by MZMs. We attribute the ZBCP, instead, to the existence of a supercurrent between two far-separated superconducting Al electrodes, which shows up as a zero-bias peak because of the circuitry and thermal fluctuations of the supercurrent phase, a mechanism conceived by Ivanchenko and Zil'berman more than 50 years ago [Ivanchenko and Zil’berman, JETP 28, 1272 (1969)]. Our results thus call for extreme caution when assigning the origin of a large ZBCP to MZMs in a multiterminal semiconductor or topological insulator/semimetal setup. We thus provide criteria for identifying when the ZBCP is definitely not caused by an MZM. Furthermore, we present several remarkable experimental results of a supercurrent effect occurring over unusually long distances and clean perfect Andreev reflection features. |
| first_indexed | 2024-04-24T10:26:26Z |
| format | Article |
| id | doaj.art-e29baa7c184f46e28ce8ac3902c4392b |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:26:26Z |
| publishDate | 2020-07-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-e29baa7c184f46e28ce8ac3902c4392b2024-04-12T16:56:27ZengAmerican Physical SocietyPhysical Review Research2643-15642020-07-012303200210.1103/PhysRevResearch.2.032002Zero-bias conductance peak in Dirac semimetal-superconductor devicesW. YuRafael HaenelM. A. RodriguezS. R. LeeF. ZhangM. FranzD. I. PikulinW. PanMajorana zero modes (MZMs), fundamental building blocks for realizing topological quantum computers, can appear at the interface between a superconductor and a topological material. One of the experimental signatures that has been widely pursued to confirm the existence of MZMs is the observation of a large, quantized zero-bias conductance peak (ZBCP) in the differential conductance measurements. In this Letter, we report observation of such a large ZBCP in junction structures of normal metal (titanium/gold Ti/Au)—Dirac semimetal (cadmium-arsenide Cd_{3}As_{2})—conventional superconductor (aluminum Al), with a value close to four times that of the normal state conductance. Our detailed analyses suggest that this large ZBCP is most likely not caused by MZMs. We attribute the ZBCP, instead, to the existence of a supercurrent between two far-separated superconducting Al electrodes, which shows up as a zero-bias peak because of the circuitry and thermal fluctuations of the supercurrent phase, a mechanism conceived by Ivanchenko and Zil'berman more than 50 years ago [Ivanchenko and Zil’berman, JETP 28, 1272 (1969)]. Our results thus call for extreme caution when assigning the origin of a large ZBCP to MZMs in a multiterminal semiconductor or topological insulator/semimetal setup. We thus provide criteria for identifying when the ZBCP is definitely not caused by an MZM. Furthermore, we present several remarkable experimental results of a supercurrent effect occurring over unusually long distances and clean perfect Andreev reflection features.http://doi.org/10.1103/PhysRevResearch.2.032002 |
| spellingShingle | W. Yu Rafael Haenel M. A. Rodriguez S. R. Lee F. Zhang M. Franz D. I. Pikulin W. Pan Zero-bias conductance peak in Dirac semimetal-superconductor devices Physical Review Research |
| title | Zero-bias conductance peak in Dirac semimetal-superconductor devices |
| title_full | Zero-bias conductance peak in Dirac semimetal-superconductor devices |
| title_fullStr | Zero-bias conductance peak in Dirac semimetal-superconductor devices |
| title_full_unstemmed | Zero-bias conductance peak in Dirac semimetal-superconductor devices |
| title_short | Zero-bias conductance peak in Dirac semimetal-superconductor devices |
| title_sort | zero bias conductance peak in dirac semimetal superconductor devices |
| url | http://doi.org/10.1103/PhysRevResearch.2.032002 |
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