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Title: Tunable Electron-Electron Interactions in LaAlO 3 / SrTiO 3 Nanostructures

The interface between the two complex oxides LaAlO 3 and SrTiO 3 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 d xz and d yz 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.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [5] ;  [2] ;  [2] ;  [4] ;  [4] ;  [3] ;  [2] ;  [2]
  1. Univ. of Science and Technology of China, Hefei (China); Univ. of Pittsburgh, PA (United States); Pittsburgh Quantum Inst., Pittsburgh, PA (United States)
  2. Univ. of Pittsburgh, PA (United States); Pittsburgh Quantum Inst., Pittsburgh, PA (United States)
  3. Univ. of Strathclyde, Glasgow (United Kingdom)
  4. Univ. of Wisconsin, Madison, WI (United States)
  5. Univ. of Pittsburgh, PA (United States);
Publication Date:
Grant/Contract Number:
FG02-06ER46327
Type:
Published Article
Journal Name:
Physical Review. X
Additional Journal Information:
Journal Volume: 6; Journal Issue: 4; Journal ID: ISSN 2160-3308
Publisher:
American Physical Society
Research Org:
Univ. of Wisconsin, Madison, WI (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS
OSTI Identifier:
1334205
Alternate Identifier(s):
OSTI ID: 1361634