Insulator-to-Metal Transition at Oxide Interfaces Induced by WO3 Overlayers

Giordano Mattoni, David J. Baek, Nicola Manca, Nils Verhagen, Dirk J. Groenendijk, Lena F. Kourkoutis, Alessio Filippetti, Andrea D. Caviglia

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)
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Abstract

Interfaces between complex oxides constitute a unique playground for two-dimensional electron systems (2DESs), where superconductivity and magnetism can arise from combinations of bulk insulators. The 2DES at the LaAlO3/SrTiO3 interface is one of the most studied in this regard, and its origin is determined by the polar field in LaAlO3 as well as by the presence of point defects, like oxygen vacancies and intermixed cations. These defects usually reside in the conduction channel and are responsible for a decrease of the electronic mobility. In this work, we use an amorphous WO3 overlayer to obtain a high-mobility 2DES in WO3/LaAlO3/SrTiO3 heterostructures. The studied system shows a sharp insulator-to-metal transition as a function of both LaAlO3 and WO3 layer thickness. Low-temperature magnetotransport reveals a strong magnetoresistance reaching 900% at 10 T and 1.5 K, the presence of multiple conduction channels with carrier mobility up to 80 000 cm2 V-1 s-1, and quantum oscillations of conductance.

Original languageEnglish
Pages (from-to)42336-42343
Number of pages8
JournalACS Applied Materials and Interfaces
Volume9
Issue number48
DOIs
Publication statusPublished - 6 Dec 2017

Keywords

  • high mobility
  • LaAlO/SrTiO interface
  • metal-insulator
  • quantum oscillations
  • strong classical magnetoresistance
  • two-dimensional electron systems
  • WO overlayers

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