Tunneling conductance due to a discrete spectrum of Andreev states
We study tunneling spectroscopy of subgap Andreev states in a superconducting system and discuss the general situation when the discrete nature of these levels is relevant and thus the standard semiclassical result for tunneling conductance being proportional to the density of states is not applicab...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2013-01-01
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| Series: | New Journal of Physics |
| Online Access: | https://doi.org/10.1088/1367-2630/15/5/055011 |
| _version_ | 1797751619137306624 |
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| author | P A Ioselevich M V Feigel'man |
| author_facet | P A Ioselevich M V Feigel'man |
| author_sort | P A Ioselevich |
| collection | DOAJ |
| description | We study tunneling spectroscopy of subgap Andreev states in a superconducting system and discuss the general situation when the discrete nature of these levels is relevant and thus the standard semiclassical result for tunneling conductance being proportional to the density of states is not applicable. If the tunneling coupling is weak, individual levels are resolved and the conductance G ( V ) at low temperatures is composed of a set of resonant Lorentz peaks which cannot be described within perturbation theory over tunneling strength. We establish a general formula for the peak widths and heights and show that the width of any peak scales as normal-state tunnel conductance, while its height is ≲2 e ^2 h ^−1 and depends only on contact geometry and the spatial profile of the resonant Andreev level. We also establish an exact formula for the single-channel conductance that takes the whole Andreev spectrum into account, and use it to study the interference of Andreev reflection processes through different levels. We study tunneling conductance at finite bias G ( eV >0) for a system with a pair of almost decoupled Majorana fermions and derive the conditions for the ‘universal’ zero-bias peak with the height 2 e ^2 / h to be observed in a realistic system which always hosts an even number of Majorana fermions. |
| first_indexed | 2024-03-12T16:52:10Z |
| format | Article |
| id | doaj.art-f606995068b34015ac8512547ee11372 |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:52:10Z |
| publishDate | 2013-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-f606995068b34015ac8512547ee113722023-08-08T11:10:10ZengIOP PublishingNew Journal of Physics1367-26302013-01-0115505501110.1088/1367-2630/15/5/055011Tunneling conductance due to a discrete spectrum of Andreev statesP A Ioselevich0M V Feigel'man1L D Landau Institute for Theoretical Physics , Kosygin Street 2, Moscow 119334, Russia; Moscow Institute of Physics and Technology , Institutsky Per. 9, Dolgoprudny 141700, RussiaL D Landau Institute for Theoretical Physics , Kosygin Street 2, Moscow 119334, Russia; Moscow Institute of Physics and Technology , Institutsky Per. 9, Dolgoprudny 141700, RussiaWe study tunneling spectroscopy of subgap Andreev states in a superconducting system and discuss the general situation when the discrete nature of these levels is relevant and thus the standard semiclassical result for tunneling conductance being proportional to the density of states is not applicable. If the tunneling coupling is weak, individual levels are resolved and the conductance G ( V ) at low temperatures is composed of a set of resonant Lorentz peaks which cannot be described within perturbation theory over tunneling strength. We establish a general formula for the peak widths and heights and show that the width of any peak scales as normal-state tunnel conductance, while its height is ≲2 e ^2 h ^−1 and depends only on contact geometry and the spatial profile of the resonant Andreev level. We also establish an exact formula for the single-channel conductance that takes the whole Andreev spectrum into account, and use it to study the interference of Andreev reflection processes through different levels. We study tunneling conductance at finite bias G ( eV >0) for a system with a pair of almost decoupled Majorana fermions and derive the conditions for the ‘universal’ zero-bias peak with the height 2 e ^2 / h to be observed in a realistic system which always hosts an even number of Majorana fermions.https://doi.org/10.1088/1367-2630/15/5/055011 |
| spellingShingle | P A Ioselevich M V Feigel'man Tunneling conductance due to a discrete spectrum of Andreev states New Journal of Physics |
| title | Tunneling conductance due to a discrete spectrum of Andreev states |
| title_full | Tunneling conductance due to a discrete spectrum of Andreev states |
| title_fullStr | Tunneling conductance due to a discrete spectrum of Andreev states |
| title_full_unstemmed | Tunneling conductance due to a discrete spectrum of Andreev states |
| title_short | Tunneling conductance due to a discrete spectrum of Andreev states |
| title_sort | tunneling conductance due to a discrete spectrum of andreev states |
| url | https://doi.org/10.1088/1367-2630/15/5/055011 |
| work_keys_str_mv | AT paioselevich tunnelingconductanceduetoadiscretespectrumofandreevstates AT mvfeigelman tunnelingconductanceduetoadiscretespectrumofandreevstates |