Tunable electron-electron interactions in LaAlO3/SrTiO3 nanostructures

Guanglei Cheng, Michelle Tomczyk, Alexandre B. Tacla, Hyungwoo Lee, Shicheng Lu, Josh P. Veazey, Mengchen Huang, Patrick Irvin, Sangwoo Ryu, Chang-Beom Eom, Andrew Daley, David Pekker, Jeremy Levy

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Abstract

The interface between the two complex oxides LaAlO3 and SrTiO3 has remarkable properties that can be locally reconfigured between conducting and insulating states using a conductive atomic force microscope. Prior investigations of "sketched" quantum dot devices revealed a phase in which electrons form pairs,
implying a strongly attractive electron-electron interaction. Here, we show that these devices with strong electron-electron interactions can exhibit a gate-tunable transition from a pair-tunneling regime to a single-electron (Andreev bound state) tunneling regime where the interactions become repulsive. The electron-electron interaction sign change is associated with a Lifshitz transition where the dxz and dyz bands start to become occupied. This electronically tunable electron-electron interaction, combined with the nanoscale
reconfigurability of this system, provides an interesting starting point towards solid-state quantum simulation.
Original languageEnglish
Article number041042
Number of pages11
JournalPhysical Review X
Volume6
Issue number4
DOIs
Publication statusPublished - 1 Dec 2016

Keywords

  • condensed matter physics
  • strongly correlated materials
  • superconductivity

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