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Grenoble : Topological superconductivity in quantum Hall edge channels
Envoyé par Benjamin Sacepe
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Grenoble : Topological superconductivity in quantum Hall edge channels vendredi 3 novembre 2023 12:25:46 |
General Scope: Graphene is a 2D material that has attracted a considerable interest since its discovery in 2005. Its gapless linear band structure that mimics massless Dirac fermions has led to the discovery of a wealth of new exciting transport properties. Moreover, the possibility to engineer very high mobility graphene devices in which electrons can travel in a ballistic fashion makes graphene the perfect playground to investigate quantum coherent phenomena in the quantum Hall regime, or when coupled with a superconducting condensate.
Research topic: Our research focuses on a new topological state of matter, the quantum Hall topological insulator that our group recently discovered in graphene [1,2]. This special quantum Hall state harbors a pair of counter-propagating, one dimensional edge channels, so-called helical edge channels, which can serve as platform to induce an unconventional superconducting state once hybridized with superconducting electrodes. One of our main objectives is to study the quantum transport properties to reveal the topological nature of this proximity-induced superconductivity, that is, the presence of Majorana zero modes, in suitably designed hybrid devices. Our group has developed state-of-the-art fabrication processes of high mobility graphene devices by encapsulation of graphene monolayers between insulating boron-nitride flakes, as well as of hybrid superconducting devices.
The objective of the Master internship is to fabricate and perform quantum transport measurements (down to T=0.01K and up to B=18T) of high-mobility graphene Josephson junctions made with a high critical-field superconductor (MoGe [3]). We have recently demonstrated the existence of a chiral supercurrent in quantum Hall Josephson junctions and this project will build on this unique expertise to unveil a helical supercurrent. These pioneer investigations of Josephson junctions in the quantum Hall topological insulator state are a first step towards coherent manipulation of Majorana bound states
[1] Helical quantum Hall phase in graphene on StrTiO3, L. Veyrat et al. Science 367, 781 (2020) arxiv:1907:02299
[2] Imaging tunable quantum Hall broken-symmetry orders in graphene, A. Coissard et al. Nature 605, 51 (2022). arxiv.org:2110.02811
[3] Evidence for chiral supercurrent in quantum Hall Josephson junctions, H. Vignaud et al. Nature in press (2023) arxiv.org:2305.01766
PhD Funding: YES (ERC grant)
Starting date: Flexible
Required skills: We look for highly motivated students with a good background in condensed matter physics / quantum physics, and which are willing to address fundamental questions at the frontier of quantum solid-states physics. Notice that lab visits are highly encouraged.
Contact: Benjamin SACEPE ( benjamin.sacepe@neel.cnrs.fr )
Website: [sacepe-quest.neel.cnrs.fr]
Modifié 1 fois. Dernière modification le 03/11/23 14:33 par Webmaster EDPIF.
Research topic: Our research focuses on a new topological state of matter, the quantum Hall topological insulator that our group recently discovered in graphene [1,2]. This special quantum Hall state harbors a pair of counter-propagating, one dimensional edge channels, so-called helical edge channels, which can serve as platform to induce an unconventional superconducting state once hybridized with superconducting electrodes. One of our main objectives is to study the quantum transport properties to reveal the topological nature of this proximity-induced superconductivity, that is, the presence of Majorana zero modes, in suitably designed hybrid devices. Our group has developed state-of-the-art fabrication processes of high mobility graphene devices by encapsulation of graphene monolayers between insulating boron-nitride flakes, as well as of hybrid superconducting devices.
The objective of the Master internship is to fabricate and perform quantum transport measurements (down to T=0.01K and up to B=18T) of high-mobility graphene Josephson junctions made with a high critical-field superconductor (MoGe [3]). We have recently demonstrated the existence of a chiral supercurrent in quantum Hall Josephson junctions and this project will build on this unique expertise to unveil a helical supercurrent. These pioneer investigations of Josephson junctions in the quantum Hall topological insulator state are a first step towards coherent manipulation of Majorana bound states
[1] Helical quantum Hall phase in graphene on StrTiO3, L. Veyrat et al. Science 367, 781 (2020) arxiv:1907:02299
[2] Imaging tunable quantum Hall broken-symmetry orders in graphene, A. Coissard et al. Nature 605, 51 (2022). arxiv.org:2110.02811
[3] Evidence for chiral supercurrent in quantum Hall Josephson junctions, H. Vignaud et al. Nature in press (2023) arxiv.org:2305.01766
PhD Funding: YES (ERC grant)
Starting date: Flexible
Required skills: We look for highly motivated students with a good background in condensed matter physics / quantum physics, and which are willing to address fundamental questions at the frontier of quantum solid-states physics. Notice that lab visits are highly encouraged.
Contact: Benjamin SACEPE ( benjamin.sacepe@neel.cnrs.fr )
Website: [sacepe-quest.neel.cnrs.fr]
Modifié 1 fois. Dernière modification le 03/11/23 14:33 par Webmaster EDPIF.