Stoichiometric control of 2D superconductivity and mobility at SrTiO<sub>3</sub>-based interfaces

ORAL

Abstract

SrTiO3-based conducting interfaces, that exhibit coexistence of gate tunable multi-orbital 2D superconductivity and strong Rashba spin-orbit coupling (RSOC), have ingredients to generate topological superconducting electronics for quantum application. However, the common challenge is to control the superconducting critical temperature (Tc) and electronic mobilities (μ) that are sensitive in 2D from defects, imperfections, cation stoichiometry, etc. originating from non-trivial synthesis process and limits the device dimension from its characteristic length. Besides, the origin conductivity and superconductivity are still debated, the numerous studies on LaAlO3/SrTiO3 interfaces suggest that superconducting condensate only forms in extreme dirty limit and suppresses strongly at low electrostatic doping below Lifshitz transition. Here we report that a small variation of Lanthanum (La) and Aluminum (Al) ratio in Al-rich LaAlO3, as identified in XPS and STEM-EELS measurements, provides an excellent degree of freedom, not yet explored, to fine-tune systematically carrier density, mobility, and strikingly formation of superconducting condensate as well. Gate tunable superconducting phase diagram display even growing Tc below Lifshitz transition attributed to the observed larger electronic mobility which is comparable to superconducting coherence length. Our result paves the way to understand the origin of superconductivity subtler way and form devices with moderate dimensions for topological superconducting electronics.

*This research was funded by ERA-NET QUANTERA European Union’s Horizon H2020 project “QUANTOX” under Grant Agreement No. 731473 and from the Beatriu de Pinós Programme and the Ministry of Research and Universities of the Government of Catalonia, with research Grant No.2019BP00207.

–

Presenters

  • Gyanendra Singh

    • Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)

Authors

  • Gyanendra Singh

    • Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)

  • Gerbold Ménard

    • Laboratoire de Physique et d'Etude des Matériaux, ESPCI Paris, PSL University, CNRS, Sorbonne Université, Paris, France.

  • Guilhem Saïz

    • Laboratoire de Physique et d'Etude des Matériaux, ESPCI Paris, PSL University, CNRS, Sorbonne Université, Paris, France

  • Roger Guzman

    • University of Chinese Academy of Sciences
    • School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences
    • University of Chinese Academy of Sciences (UCAS), Beijing, China

  • Roger Guzman

    • University of Chinese Academy of Sciences
    • School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences
    • University of Chinese Academy of Sciences (UCAS), Beijing, China

  • Jordi Fraxedas

    • Catalan Institute of Nanoscience and Nanotechnology
    • Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona 08193, Spain

  • Jaume Gázquez

    • Institut de Ciéncia de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Catalonia, Spain

  • Gervasi Herranz

    • ICMAB-CSIC
    • Institute for Materials Science of Barcelona ICMAB-CSIC
    • Institut de Ciéncia de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Catalonia, Spain

  • Nicolas Bergeal

    • Laboratoire de Physique et d'Etude des Matériaux, ESPCI Paris, PSL University, CNRS, Sorbonne Université, Paris, France.

  • Alexei Kalaboukhov

    • Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE 41296 Gothenburg, Sweden.