Back to Search Start Over

Probing charge transfer during metal-insulator transitions in graphene-LaAlO3/SrTiO3 systems

Authors :
I. Aliaj
A. Sambri
V. Miseikis
D. Stornaiuolo
E. di Gennaro
C. Coletti
V. Pellegrini
F. Miletto Granozio
S. Roddaro
Source :
APL Materials, Vol 6, Iss 6, Pp 066103-066103-7 (2018)
Publication Year :
2018
Publisher :
AIP Publishing LLC, 2018.

Abstract

Two-dimensional electron systems (2DESs) at the interface between LaAlO3 (LAO) and SrTiO3 (STO) perovskite oxides display a wide class of tunable phenomena ranging from superconductivity to metal-insulator transitions. Most of these effects are strongly sensitive to surface physics and often involve charge transfer mechanisms, which are, however, hard to detect. In this work, we realize hybrid field-effect devices where graphene is used to modulate the transport properties of the LAO/STO 2DES. Different from a conventional gate, graphene is semimetallic and allows us to probe charge transfer with the oxide structure underneath the field-effect electrode. In LAO/STO samples with a low initial carrier density, graphene-covered regions turn insulating when the temperature is lowered to 3 K, but conduction can be restored in the oxide structure by increasing the temperature or by field effect. The evolution of graphene’s electron density is found to be inconsistent with a depletion of LAO/STO, but it rather points to a localization of interfacial carriers in the oxide structure.

Details

Language :
English
ISSN :
2166532X
Volume :
6
Issue :
6
Database :
Directory of Open Access Journals
Journal :
APL Materials
Publication Type :
Academic Journal
Accession number :
edsdoj.120ada858b084007959b1bf97ce57f36
Document Type :
article
Full Text :
https://doi.org/10.1063/1.5026912