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

Guenevere E. D. K. Prawiroatmodjo, Martin Christian Leijnse, Felix Trier, Yunzhong Chen, Dennis Valbjørn Christensen, Merlin von Soosten, Nini Pryds, Thomas Sand Jespersen

Research output: Contribution to journalJournal articlepeer-review

303 Downloads (Pure)

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 Tc 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.
Original languageEnglish
Article number395
JournalNature Communications
Volume8
Issue number1
Number of pages7
ISSN2041-1723
DOIs
Publication statusPublished - 2017

Fingerprint

Dive into the research topics of 'Transport and excitations in a negative-U quantum dot at the LaAlO<sub>3</sub>/SrTiO<sub>3</sub> interface'. Together they form a unique fingerprint.

Cite this