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Field-effect control of superconductivity and Rashba spin-orbit coupling in top-gated LaAlO3/SrTiO3 devices.

Hurand S, Jouan A, Feuillet-Palma C, Singh G, Biscaras J, Lesne E, Reyren N, Barthélémy A, Bibes M, Villegas JE, Ulysse C, Lafosse X, Pannetier-Lecoeur M, Caprara S, Grilli M, Lesueur J, Bergeal N - Sci Rep (2015)

Bottom Line: Here, we report on the realisation of a field-effect LaAlO3/SrTiO3 device, whose physical properties, including superconductivity and SOC, can be tuned over a wide range by a top-gate voltage.We derive a phase diagram, which emphasises a field-effect-induced superconductor-to-insulator quantum phase transition.Our results pave the way for the realisation of mesoscopic devices, where these two properties can be manipulated on a local scale by means of top-gates.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Physique et d'Etude des Matériaux -CNRS-ESPCI ParisTech-UPMC, PSL Research University, 10 Rue Vauquelin, 75005 Paris, France.

ABSTRACT
The recent development in the fabrication of artificial oxide heterostructures opens new avenues in the field of quantum materials by enabling the manipulation of the charge, spin and orbital degrees of freedom. In this context, the discovery of two-dimensional electron gases (2-DEGs) at LaAlO3/SrTiO3 interfaces, which exhibit both superconductivity and strong Rashba spin-orbit coupling (SOC), represents a major breakthrough. Here, we report on the realisation of a field-effect LaAlO3/SrTiO3 device, whose physical properties, including superconductivity and SOC, can be tuned over a wide range by a top-gate voltage. We derive a phase diagram, which emphasises a field-effect-induced superconductor-to-insulator quantum phase transition. Magneto-transport measurements show that the Rashba coupling constant increases linearly with the interfacial electric field. Our results pave the way for the realisation of mesoscopic devices, where these two properties can be manipulated on a local scale by means of top-gates.

No MeSH data available.


Related in: MedlinePlus

Magnetotransport measurements.(a) Magnetoconductance of the device at T = 3.5 K for different VTG. The experimental data (open symbols) are fitted with the Maekawa-Fukuyama formula (1). (b) Evolution of the fitting parameters BSO, Bϕ and AK as a function of the gate voltage. Inset) Variations in BSO and Bϕ as a function of temperature for VTG = 0.
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f4: Magnetotransport measurements.(a) Magnetoconductance of the device at T = 3.5 K for different VTG. The experimental data (open symbols) are fitted with the Maekawa-Fukuyama formula (1). (b) Evolution of the fitting parameters BSO, Bϕ and AK as a function of the gate voltage. Inset) Variations in BSO and Bϕ as a function of temperature for VTG = 0.

Mentions: The weak localization corrections to the conductance of a two-dimensionnal system at low temperatures are modified by the presence of an additional spin relaxation mechanism due to SOC2526 whose strength can therefore be determined by properly analysing the magnetoconductance Δσ(B) = σ(B) − σ(0). Δσ(B) was measured in the normal state at different temperatures and top-gate voltages. For negative VTG a positive magnetoconductance was observed beyond 1 T. This is characteristic of a weak localization regime with small SOC (Fig. 4). As VTG is increased, an inversion of the sign of the magnetoconductance is observed and at large positive gate voltages the magnetoconductance remains always negative. The experimental data in Fig. 4 were fitted with the Maekawa-Fukuyama formula in a diffusive regime that describes the change in the conductivity with magnetic field with negligible Zeeman splitting25,


Field-effect control of superconductivity and Rashba spin-orbit coupling in top-gated LaAlO3/SrTiO3 devices.

Hurand S, Jouan A, Feuillet-Palma C, Singh G, Biscaras J, Lesne E, Reyren N, Barthélémy A, Bibes M, Villegas JE, Ulysse C, Lafosse X, Pannetier-Lecoeur M, Caprara S, Grilli M, Lesueur J, Bergeal N - Sci Rep (2015)

Magnetotransport measurements.(a) Magnetoconductance of the device at T = 3.5 K for different VTG. The experimental data (open symbols) are fitted with the Maekawa-Fukuyama formula (1). (b) Evolution of the fitting parameters BSO, Bϕ and AK as a function of the gate voltage. Inset) Variations in BSO and Bϕ as a function of temperature for VTG = 0.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525493&req=5

f4: Magnetotransport measurements.(a) Magnetoconductance of the device at T = 3.5 K for different VTG. The experimental data (open symbols) are fitted with the Maekawa-Fukuyama formula (1). (b) Evolution of the fitting parameters BSO, Bϕ and AK as a function of the gate voltage. Inset) Variations in BSO and Bϕ as a function of temperature for VTG = 0.
Mentions: The weak localization corrections to the conductance of a two-dimensionnal system at low temperatures are modified by the presence of an additional spin relaxation mechanism due to SOC2526 whose strength can therefore be determined by properly analysing the magnetoconductance Δσ(B) = σ(B) − σ(0). Δσ(B) was measured in the normal state at different temperatures and top-gate voltages. For negative VTG a positive magnetoconductance was observed beyond 1 T. This is characteristic of a weak localization regime with small SOC (Fig. 4). As VTG is increased, an inversion of the sign of the magnetoconductance is observed and at large positive gate voltages the magnetoconductance remains always negative. The experimental data in Fig. 4 were fitted with the Maekawa-Fukuyama formula in a diffusive regime that describes the change in the conductivity with magnetic field with negligible Zeeman splitting25,

Bottom Line: Here, we report on the realisation of a field-effect LaAlO3/SrTiO3 device, whose physical properties, including superconductivity and SOC, can be tuned over a wide range by a top-gate voltage.We derive a phase diagram, which emphasises a field-effect-induced superconductor-to-insulator quantum phase transition.Our results pave the way for the realisation of mesoscopic devices, where these two properties can be manipulated on a local scale by means of top-gates.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Physique et d'Etude des Matériaux -CNRS-ESPCI ParisTech-UPMC, PSL Research University, 10 Rue Vauquelin, 75005 Paris, France.

ABSTRACT
The recent development in the fabrication of artificial oxide heterostructures opens new avenues in the field of quantum materials by enabling the manipulation of the charge, spin and orbital degrees of freedom. In this context, the discovery of two-dimensional electron gases (2-DEGs) at LaAlO3/SrTiO3 interfaces, which exhibit both superconductivity and strong Rashba spin-orbit coupling (SOC), represents a major breakthrough. Here, we report on the realisation of a field-effect LaAlO3/SrTiO3 device, whose physical properties, including superconductivity and SOC, can be tuned over a wide range by a top-gate voltage. We derive a phase diagram, which emphasises a field-effect-induced superconductor-to-insulator quantum phase transition. Magneto-transport measurements show that the Rashba coupling constant increases linearly with the interfacial electric field. Our results pave the way for the realisation of mesoscopic devices, where these two properties can be manipulated on a local scale by means of top-gates.

No MeSH data available.


Related in: MedlinePlus