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Two-dimensional electron gas at oxides interfaces


Transition metal oxides have attracted much attention in recent decades for the richness of their phase diagrams that reveal a variety of electronic properties ranging from high-Tc superconductivity to colossal magnetoresistance. As these materials have comparable lattice parameters, they can be combined artificial heterostructures with atomically flat interface, which provides unique opportunities for the generation of novel emergent properties and functionalities. In this context, the discovery of a superconducting two-dimensional electron gas at the interface between two insulating oxides such as LaAlO3 and SrTiO3 has generated a considerable interest. In these heterostructures, the 2-DEG is confined in an interfacial quantum well that extends to approximately 10 nm into the SrTiO3 substrate at low temperature. The superconducting transition temperature Tc can be tuned over a wide range by means of electrostatic gating, which allows a superconducting phase diagram of this interface to be derived. The breaking of translational symmetry in the interfacial quantum well also generates a spin-orbit coupling of Rashba type, whose strength can be tuned by a gate voltage.
The PHASME team studies the properties of these electronic systems by dc and microwave low-temperature electronic transport.

Main references :

  • Superfluid stiffness of a KTaO3-based two-dimensional electron gas. S. Mallik, G. Ménard, G. Saïz, H. Witt, J. Lesueur, A. Gloter, L. Benfatto, M. Bibes, N. Bergeal.
    Nature Commun. 13, 4625 (2022)
  • Multiband effects in the superconducting phase diagram of oxide interfaces. A. Jouan, S. Hurand, G. Singh, E. Lesne, A. Barthélémy, M. Bibes, C. Ulysse, G. Saiz , C. Feuillet-Palma, J. Lesueur and N. Bergeal.
    Adv. Mat. Int. (2022) https://doi.org/10.1002/admi.202201392
  • Two-gap s±-wave superconductivity at an oxide interface G. Singh, G. Venditti, G. Saiz, G. Herranz, F. Sánchez, A. Jouan, C. Feuillet-Palma, J. Lesueur, M. Grilli, S. Caprara, and N. Bergeal
    Phys. Rev. B 105, 064512 (2022)
  • Quantized conductance in a one-dimensional ballistic oxide nanodevice. 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
    Nature Elec. 3, 201–206 (2020)
  • Gap suppression at a Lifshitz transition in a multi-condensate superconductor G. Singh1, A. Jouan, G. Herranz, M. Scigaj, F. Sanchez, L. Benfatto, S. Caprara, M. Grilli, F. Couedo, C. Feuillet-Palma, J. Lesueur, N. Bergeal
    Nature Mat. 18, 948–954 (2019)
  • Josephson-like dynamics of the superconducting LaAlO3/SrTiO3 interface. S. Hurand, A. Jouan, E. Lesne, G. Singh, C. Feuillet-Palma, M. Bibes, A. Barthélémy, J. Lesueur & N. Bergeal
    Phys. Rev. B. 99, 104515 (2019)
  • Competition between electron pairing and phase coherence in superconducting interfaces G. Singh, A. Jouan, L. Benfatto, F. Couedo, P. Kumar, A. Dogra, R. Budhani, S. Caprara, M. Grilli, E. Lesne, A. Barthelemy, M. Bibes, C. Feuillet-Palma, J. Lesueur, N. Bergeal
    Nature Commun. 5,407 (2018)
  • Effect of disorder on superconductivity and Rashba spin-orbit coupling in LaAlO3/SrTiO3 interfaces G. Singh, A. Jouan, S. Hurand, C. Palma, P. Kumar, A. Dogra, R. Budhani, J. Lesueur and N. Bergeal
    Phys. Rev. B 96, 024509 (2017)
  • Top-gated field-effect LaAlO3/SrTiO3 devices made by ion-irradiation S. Hurand, A. Jouan, C. Feuillet-Palma, G. Singh, E. Lesne, N. Reyren, A. Barthelemy, M. Bibes, J. E. Villegas, C. Ulysse, M. Pannetier-Lecoeur, M. Malnou, J. Lesueur, N. Bergeal
    Appl. Phys. Lett. 108, 052602 (2016)
  • Engineering 2D-superconductivity and Rashba spin-orbit coupling by selective orbital occupancy G. Herranz, G. Singh, N. Bergeal, A. Jouan, J. Lesueur, J. Gazquez, M. Varela, M. Scigaj, N. Dix, F. Sanchez and J. Fontcuberta
    Nature Commun. 6, 6028 (2015)
  • Field-effect control of superconductivity and Rashba spin-orbit coupling in top-gated LaAlO3/SrTiO3 devices S. Hurand, A. Jouan, C. Feuillet-Palma, G. Singh, J. Biscaras, E. Lesne, N. Reyren, A. Barthélémy, M. Bibes, J. E. Villegas, C. Ulysse, X. Lafosse, M. Pannetier-Lecoeur, S. Caprara, M. Grilli, J. Lesueur & N. Bergeal
    Sci. Rep. 5, 12751 (2015)
  • Limit of the electrostatic doping in two-dimensional electron gases of LaAlO3/SrTiO3
    J. Biscaras, S. Hurand, C. Feuillet-Palma, A. Rastogi, R. C. Budhani, N. Reyren, E. Lesne, J. Lecteur and N. Bergeal
    Sci. Rep. 4, 6788 (2014)
  • Two-dimensional superconducting phase in LaTiO3/SrTiO3 heterostructures induced by high-mobility carrier doping J. Biscaras, N. Bergeal, S. Hurand, C. Grossetete, A. Rastogi, R. C. Budhani, D. LeBoeuf, C. Proust, and J. Lesueur,
    Phys. Rev. Lett. 108, 247004 (2012)
  • Two-dimensional Superconductivity at a Mott-Insulator/Band-Insulator interface: LaTiO3/SrTiO3, J. Biscaras, N. Bergeal, A.K. Kushwaha, T. Wolf, A. Gangawar, R.C. Budhani and J. Lesueur
    Nature Commun. 1, 89 (2010)

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