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Two-dimensional superconductivity at a Mott insulator/band insulator interface LaTiO3/SrTiO3
J Biscaras1, N Bergeal, A Kushwaha
1Laboratoire de Physique et d'Etude des Matériaux, UMR8213/CNRS, ESPCI ParisTech, 10 rue Vauquelin, Paris 75005, France.
Nature Communications
|October 29, 2010
Summary
Superconductivity emerges in LaTiO(3)/SrTiO(3) heterostructures, forming a two-dimensional electron gas primarily within the SrTiO(3) layer. This finding offers new insights into electronic behavior at interfaces of transition metal oxides.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Electronics
Background:
- Transition metal oxides exhibit diverse quantum electronic behaviors influenced by electron correlations.
- Epitaxial interfaces of these oxides enable engineering of novel electronic orders.
- A two-dimensional electron gas (2DEG) was previously observed at LaTiO(3)/SrTiO(3) interfaces, but its formation mechanism remains debated.
Purpose of the Study:
- To investigate the superconducting properties of LaTiO(3)/SrTiO(3) heterostructures.
- To clarify the role of the insulating layer's nature in interfacial electronic phenomena.
- To determine the characteristics of the superconducting electron gas.
Main Methods:
- Fabrication of high-quality epitaxial LaTiO(3)/SrTiO(3) heterostructures.
- Experimental characterization of electronic transport properties.
- Determination of the superconducting critical temperature (T(c)) and electron gas localization.
Main Results:
- LaTiO(3)/SrTiO(3) heterostructures exhibit a superconducting transition with an onset critical temperature of approximately 300 mK.
- The superconducting electron gas is confined to a thickness of about 12 nm.
- The majority of the superconducting charge carriers are located on the SrTiO(3) substrate side of the interface.
Conclusions:
- Superconductivity is demonstrated in LaTiO(3)/SrTiO(3) heterostructures, despite the strong electronic correlations expected.
- The findings suggest that the superconducting state is intimately linked to the SrTiO(3) component of the interface.
- This work contributes to understanding interfacial superconductivity in correlated electron systems.
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