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Portrait of Martin Leijnse; Photo: Kennet Ruona

Martin Leijnse

Professor, Member of NanoLund Management Group

Portrait of Martin Leijnse; Photo: Kennet Ruona

Transport and excitations in a negative-U quantum dot at the LaAlO3/SrTiO3 interface


  • Guenevere E.D.K. Prawiroatmodjo
  • Martin Leijnse
  • Felix Trier
  • Yunzhong Chen
  • Dennis V. Christensen
  • Merlin Von Soosten
  • Nini Pryds
  • Thomas S. Jespersen

Summary, in English

In a solid-state host, attractive electron-electron interactions can lead to the formation of local electron pairs which play an important role in the understanding of prominent phenomena such as high T c superconductivity and the pseudogap phase. Recently, evidence of a paired ground state without superconductivity was demonstrated at the level of single electrons in quantum dots at the interface of LaAlO3 and SrTiO3. Here, we present a detailed study of the excitation spectrum and transport processes of a gate-defined LaAlO3/SrTiO3 quantum dot exhibiting pairing at low temperatures. For weak tunneling, the spectrum agrees with calculations based on the Anderson model with a negative effective charging energy U, and exhibits an energy gap corresponding to the Zeeman energy of the magnetic pair-breaking field. In contrast, for strong coupling, low-bias conductance is enhanced with a characteristic dependence on temperature, magnetic field and chemical potential consistent with the charge Kondo effect.


  • Solid State Physics
  • NanoLund: Center for Nanoscience

Publishing year





Nature Communications





Document type

Journal article


Nature Publishing Group


  • Condensed Matter Physics




  • ISSN: 2041-1723