PHASME

Superﬂuid stiffness of a KTaO3-based two-dimensional electron gas

Nicolas Bergeal — 2022-08-13T09:15:52Z

S. Mallik, G. C. Ménard, L. Benfatto, M. Bibes, G. Saïz, H. Witt, J. Lesueur & N. Bergeal
After almost twenty years of intense work on the celebrated LaAlO3 /SrTiO3 system, the recent discovery of a superconducting two-dimensional electron gas (2-DEG) in (111)-oriented KTaO3 -based heterostructures injects new momentum to the ﬁeld of oxides interface. However, while both interfaces share common properties, experiments also suggest important differences between the two systems. Here, we (…)

- Selected Publications

Quantized conductance in a one-dimensional ballistic oxide nanodevice

Nicolas Bergeal — 2020-03-19T15:57:24Z

A. Jouan, G. Singh, E. Lesne, D. C. Vaz, M. Bibes, A. Barthélémy, C. Ulysse, D. Stornaiuolo, M. Salluzzo, S. Hurand, J. Lesueur, C. Feuillet-Palma & N. Bergeal
The electric-field effect control of two-dimensional electron gases (2-DEGs) has allowed nanoscale electron quantum transport to be explored in semiconductors. Structures based on transition metal oxides have electronic states that favour the emergence of novel quantum orders that are absent in conventional semiconductors and (…)

- Selected Publications

Gap suppression at a Lifshitz transition in a multi-condensate superconductor

Nicolas Bergeal — 2019-06-03T09:39:44Z

G. Singh, A. Jouan, G. Herranz, M. Scigaj, F. Sánchez, L. Benfatto, S. Caprara, M. Grilli, G. Saiz, F. Couëdo, C. Feuillet-Palma, J. Lesueur and N. Bergeal
In multi-orbital materials, superconductivity can exhibit several coupled condensates. In this context, quantum confinement in two-dimensional superconducting oxide interfaces offers new degrees of freedom to engineer the band structure and selectively control the occupancy of 3d orbitals by electrostatic doping. Here, we use resonant (…)

- Selected Publications

Josephson-like dynamics of the superconducting LaAlO3/SrTiO3 interface

Nicolas Bergeal — 2019-06-03T09:22:28Z

by S. Hurand, A. Jouan, E. Lesne, G. Singh, C. Feuillet-Palma, M. Bibes, A. Barthélémy, J. Lesueur, and N. Bergeal
In this article, we show that the two-dimensional electron gas formed at the LaAlO3/SrTiO3 interface behaves as a Josephson junction array. In particular, it exhibits a stochastic switching of the superconducting critical current, which qualitatively follows the dynamics of the resistively and capacitively shunted Josephson junction model. The switching current distribution (…)

- Selected Publications

Competition between electron pairing and phase coherence in superconducting interfaces

Nicolas Bergeal — 2018-05-02T12:12:05Z

by G. Singh, A. Jouan, L. Benfatto, F. Couëdo, P. Kumar, A. Dogra, R.C. Budhani, S. Caprara, M. Grilli, E. Lesne, A. Barthélémy, M. Bibes, C. Feuillet-Palma, J. Lesueur & N. Bergeal
In LaAlO3/SrTiO3 heterostructures, a gate tunable superconducting electron gas is confined in a quantum well at the interface between two insulating oxides. Remarkably, the gas coexists with both magnetism and strong Rashba spin–orbit coupling. However, both the origin of superconductivity and the nature (…)

- Selected Publications

High-temperature superconducting nanomeanders made by ion irradiation

Nicolas Bergeal — 2018-01-19T15:02:28Z

by P. Amari, C. Feuillet-Palma , A. Jouan, F. Couëdo, N. Bourlet,
E. Géron, M. Malnou, L. Méchin, A. Sharafiev, J. Lesueur and
N. Bergeal
In this article, we report on the fabrication of very long YBa2Cu3O7 nanowires in a meander shape patterned in a CeO2-capped thin film by high-energy oxygen ion irradiation. DC and RF characterizations outline the good superconducting properties of the nanowires whose geometry approaches the one used in single photon detectors. Their inductance, which (…)

- Selected Publications

Effect of disorder on superconductivity and Rashba spin-orbit coupling in LaAlO3/SrTiO3 interfaces

Nicolas Bergeal — 2018-01-19T14:52:38Z

by G. Singh, A. Jouan, S. Hurand, C. Feuillet-Palma, P. Kumar, A. Dogra,
R. Budhani, J. Lesueur and N. Bergeal
A rather unique feature of the two-dimensional electron gas formed at the interface between the two insulators LaAlO3 and SrTiO3 is to host both gate-tunable superconductivity and strong spin-orbit coupling. In the present work, we use the disorder generated by Cr substitution of Al atoms in LaAlO3 as a tool to explore the nature of superconductivity and spin-orbit coupling in (…)

- Selected Publications

Engineering two-dimensional superconductivity and Rashba spin-orbit coupling in LaAlO3/SrTiO3 quantum wells by selective orbital occupancy

Alexis Jouan — 2015-09-30T11:27:13Z

by Gervasi Herranz, Gyanendra Singh, Nicolas Bergeal, Alexis Jouan, Jérôme Lesueur, Jaume Gázquez, María Varela, Mateusz Scigaj, Nico Dix, Florencio Sánchez and Josep Fontcuberta
The discovery of two-dimensional electron gases (2DEGs) at oxide interfaces—involving electrons in narrow d-bands—has broken new ground, enabling the access to correlated states that are unreachable in conventional semiconductors based on s- and p- electrons. There is a growing consensus that emerging properties (…)

- Selected Publications

Field-effect control of superconductivity and Rashba spint-orbit coupling in top-gated LaAlO3/SrTiO3 devices

Alexis Jouan — 2015-09-29T15:54:10Z

by S. Hurand, A. Jouan, C. Feuillet-Palma, G. Singh, J. Biscaras, E. Lesne, N. Reyen, C. Ulysse, X. Lafosse, M. Pannetier-Lecoeur, S. Caprara, M. Grilli, J. Lesueur, N. Bergeal
The recent development in the fabrication of artificial oxide heterostructures opens new avenues in the field of quantum materials by enabling the manipulation of the charge, spin and orbital degrees of freedom. In this context, the discovery of two-dimensional electron gases (2-DEGs) at LaAlO3/ SrTiO3 interfaces, (…)

- Selected Publications

Physics and Applications of Superconducting and Magnetic Elements

2015-02-07T18:41:36Z

WELCOME to the PHASME group website
The PHASME group studies nanostructures of superconductors and strongly correlated systems, from basic science to applications in electromagnetic waves and photons detection. We perform electronic transport measurements from 10 mK to 300 K and from DC to 800 GHz.
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