Salvato in:
| Autori principali: | , , |
|---|---|
| Natura: | Preprint |
| Pubblicazione: |
2025
|
| Soggetti: | |
| Accesso online: | https://arxiv.org/abs/2511.05601 |
| Tags: |
Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
|
| _version_ | 1866912695630954496 |
|---|---|
| author | Xie, Cheng-Rong Tsuchiura, Hiroki Sigrist, Manfred |
| author_facet | Xie, Cheng-Rong Tsuchiura, Hiroki Sigrist, Manfred |
| contents | We study the Josephson diode effect realized purely by geometry in a Kitaev-ladder Josephson junction composed of two parallel spinless $p$-wave chains coupled by an interleg hopping $t_\perp$. The junction is governed by two phases: the superconducting phase difference across the weak link, $θ$, and the leg-to-leg phase difference, $ϕ$. For $ϕ\notin \{0, π\}$ (mod $2π$), time-reversal symmetry is broken, and the absence of leg-exchange symmetry leads to a breakdown of the antisymmetry of the current-phase relation, yielding nonreciprocal Josephson transport without magnetic fields or spin-orbit coupling. By resolving transport into bonding and antibonding channels defined by $t_\perp$, it is shown that the leg phase acts as an effective phase shift for interband ($p_ν/p_{-ν}$) tunneling, whereas the same-band ($p_ν/p_ν$) contribution remains unshifted. These channels arise at different perturbative orders and, together with the $4π$-periodic Majorana channel that emerges near the topological transition, interfere to produce a pronounced diode response. The class-D Pfaffian invariant identifies the parameter regime where the ladder hosts Majorana zero modes. Bogoliubov-de Gennes calculations reveal a dome-like dependence of the diode efficiency $η$ on $t_\perp$: $η\to 0$ for $t_\perp\to 0$ and for large $t_\perp$, with a maximum at intermediate coupling that is tunable by $ϕ$. The present results establish a field-free, geometry-based route to superconducting rectification in one-dimensional topological systems and specify symmetry and topology conditions for optimizing the effect in ladder and network devices. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_05601 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Josephson Diode Effect for a Kitaev Ladder System Xie, Cheng-Rong Tsuchiura, Hiroki Sigrist, Manfred Superconductivity We study the Josephson diode effect realized purely by geometry in a Kitaev-ladder Josephson junction composed of two parallel spinless $p$-wave chains coupled by an interleg hopping $t_\perp$. The junction is governed by two phases: the superconducting phase difference across the weak link, $θ$, and the leg-to-leg phase difference, $ϕ$. For $ϕ\notin \{0, π\}$ (mod $2π$), time-reversal symmetry is broken, and the absence of leg-exchange symmetry leads to a breakdown of the antisymmetry of the current-phase relation, yielding nonreciprocal Josephson transport without magnetic fields or spin-orbit coupling. By resolving transport into bonding and antibonding channels defined by $t_\perp$, it is shown that the leg phase acts as an effective phase shift for interband ($p_ν/p_{-ν}$) tunneling, whereas the same-band ($p_ν/p_ν$) contribution remains unshifted. These channels arise at different perturbative orders and, together with the $4π$-periodic Majorana channel that emerges near the topological transition, interfere to produce a pronounced diode response. The class-D Pfaffian invariant identifies the parameter regime where the ladder hosts Majorana zero modes. Bogoliubov-de Gennes calculations reveal a dome-like dependence of the diode efficiency $η$ on $t_\perp$: $η\to 0$ for $t_\perp\to 0$ and for large $t_\perp$, with a maximum at intermediate coupling that is tunable by $ϕ$. The present results establish a field-free, geometry-based route to superconducting rectification in one-dimensional topological systems and specify symmetry and topology conditions for optimizing the effect in ladder and network devices. |
| title | Josephson Diode Effect for a Kitaev Ladder System |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2511.05601 |