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

Prawiroatmodjo, Guenevere E.D.K.; Leijnse, Martin LU ; Trier, Felix; Chen, Yunzhong; Christensen, Dennis V.; Von Soosten, Merlin; Pryds, Nini and Jespersen, Thomas S. (2017) In Nature Communications 8(1).
Abstract

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... (More)

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.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Nature Communications
volume
8
issue
1
publisher
Nature Publishing Group
external identifiers
  • scopus:85028547465
  • wos:000408695100012
ISSN
2041-1723
DOI
10.1038/s41467-017-00495-7
language
English
LU publication?
yes
id
fbf90b1c-bccd-41fe-bafd-7ae35a2b6e87
date added to LUP
2017-09-25 14:01:45
date last changed
2018-05-06 04:36:54
@article{fbf90b1c-bccd-41fe-bafd-7ae35a2b6e87,
  abstract     = {<p>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 <sub>c</sub> 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 LaAlO<sub>3</sub> and SrTiO<sub>3</sub>. Here, we present a detailed study of the excitation spectrum and transport processes of a gate-defined LaAlO<sub>3</sub>/SrTiO<sub>3</sub> 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.</p>},
  articleno    = {395},
  author       = {Prawiroatmodjo, Guenevere E.D.K. and Leijnse, Martin and Trier, Felix and Chen, Yunzhong and Christensen, Dennis V. and Von Soosten, Merlin and Pryds, Nini and Jespersen, Thomas S.},
  issn         = {2041-1723},
  language     = {eng},
  month        = {12},
  number       = {1},
  publisher    = {Nature Publishing Group},
  series       = {Nature Communications},
  title        = {Transport and excitations in a negative-U quantum dot at the LaAlO<sub>3</sub>/SrTiO<sub>3</sub> interface},
  url          = {http://dx.doi.org/10.1038/s41467-017-00495-7},
  volume       = {8},
  year         = {2017},
}