Spectroscopic evidence for a first-order transition to the orbital Fulde-Ferrell-Larkin-Ovchinnikov state

Fuente: arXiv
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Main Authors: Cao, Zongzheng, Liao, Menghan, Yan, Hongyi, Zhu, Yuying, Zhang, Liguo, Watanabe, Kenji, Taniguchi, Takashi, Morpurgo, Alberto F., Liu, Haiwen, Xue, Qi-Kun, Zhang, Ding
Format: Preprint
Published: 2024
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author Cao, Zongzheng
Liao, Menghan
Yan, Hongyi
Zhu, Yuying
Zhang, Liguo
Watanabe, Kenji
Taniguchi, Takashi
Morpurgo, Alberto F.
Liu, Haiwen
Xue, Qi-Kun
Zhang, Ding
author_facet Cao, Zongzheng
Liao, Menghan
Yan, Hongyi
Zhu, Yuying
Zhang, Liguo
Watanabe, Kenji
Taniguchi, Takashi
Morpurgo, Alberto F.
Liu, Haiwen
Xue, Qi-Kun
Zhang, Ding
contents A conventional superconducting state may be replaced by another dissipationless state hosting Cooper pairs with a finite momentum, leaving thermodynamic footprints for such a phase transition. Recently, a novel type of finite momentum pairing, so-called orbital Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, has been proposed to occur in spin-orbit coupled superconductors such as bilayer $2\mathrm{H-NbSe_{2}}$. So far, a thermodynamic demonstration, which is key for establishing this exotic phase, has been lacking. Here, we reveal a first-order quantum phase transition to the orbital FFLO state in tunneling spectroscopic measurements on multilayer $2\mathrm{H-NbSe_{2}}$. The phase transition manifests itself as a sudden enhancement of the superconducting gap at an in-plane magnetic field $B_{//}$ well below the upper critical field. Furthermore, this transition shows prominent hysteresis by sweeping $B_{//}$ back and forth and quickly disappears once the magnetic field is tilted away from the sample plane by less than one degree. We obtain a comprehensive phase diagram for the orbital FFLO state and compare it with the theoretical calculation that takes into account the rearrangement of Josephson vortices. Our work elucidates the microscopic mechanism for the emergence of the orbital FFLO state.
format Preprint
id arxiv_https___arxiv_org_abs_2409_00373
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Spectroscopic evidence for a first-order transition to the orbital Fulde-Ferrell-Larkin-Ovchinnikov state
Cao, Zongzheng
Liao, Menghan
Yan, Hongyi
Zhu, Yuying
Zhang, Liguo
Watanabe, Kenji
Taniguchi, Takashi
Morpurgo, Alberto F.
Liu, Haiwen
Xue, Qi-Kun
Zhang, Ding
Superconductivity
A conventional superconducting state may be replaced by another dissipationless state hosting Cooper pairs with a finite momentum, leaving thermodynamic footprints for such a phase transition. Recently, a novel type of finite momentum pairing, so-called orbital Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, has been proposed to occur in spin-orbit coupled superconductors such as bilayer $2\mathrm{H-NbSe_{2}}$. So far, a thermodynamic demonstration, which is key for establishing this exotic phase, has been lacking. Here, we reveal a first-order quantum phase transition to the orbital FFLO state in tunneling spectroscopic measurements on multilayer $2\mathrm{H-NbSe_{2}}$. The phase transition manifests itself as a sudden enhancement of the superconducting gap at an in-plane magnetic field $B_{//}$ well below the upper critical field. Furthermore, this transition shows prominent hysteresis by sweeping $B_{//}$ back and forth and quickly disappears once the magnetic field is tilted away from the sample plane by less than one degree. We obtain a comprehensive phase diagram for the orbital FFLO state and compare it with the theoretical calculation that takes into account the rearrangement of Josephson vortices. Our work elucidates the microscopic mechanism for the emergence of the orbital FFLO state.
title Spectroscopic evidence for a first-order transition to the orbital Fulde-Ferrell-Larkin-Ovchinnikov state
topic Superconductivity
url https://arxiv.org/abs/2409.00373