A high-mobility electronic system at an electrolyte-gated oxide surface

Abstract

Electrolyte gating is a powerful technique for accumulating large carrier densities in surface two-dimensional electron systems (2DES). Yet this approach suffers from significant sources of disorder: electrochemical reactions can damage or alter the surface of interest, and the ions of the electrolyte and various dissolved contaminants sit Angstroms from the 2DES. Accordingly, electrolyte gating is well-suited to studies of superconductivity and other phenomena robust to disorder, but of limited use when reactions or disorder must be avoided. Here we demonstrate that these limitations can be overcome by protecting the sample with a chemically inert, atomically smooth sheet of hexagonal boron nitride (BN). We illustrate our technique with electrolyte-gated strontium titanate, whose mobility improves more than tenfold when protected with BN. We find this improvement even for our thinnest BN, of measured thickness 6 A, with which we can accumulate electron densities nearing 10^14 cm^-2. Our technique is portable to other materials, and should enable future studies where high carrier density modulation is required but electrochemical reactions and surface disorder must be minimized.

References in corpus (17)

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• Proton transport through one atom thick crystals
• Non-saturating magnetoresistance in heavily disordered semiconductors
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• Insulating behavior at the neutrality point in dual-gated, single-layer graphene
• Phase diagram of electrostatically doped Strontium Titanate (SrTiO3)
• Defect engineering in oxide heterostructures by enhanced oxygen surface exchange
• Electrostatic charge accumulation versus electrochemical doping in SrTiO3 electric double layer transistors
• Quantum longitudinal and Hall transport at the LaAlO3/SrTiO3 interface at low electron densities
• Mechanism for the Large Conductance Modulation in Electrolyte-gated Thin Gold Films
• Anomalous response to gate voltage application in mesoscopic LaAlO_3/SrTiO_3 devices
• Universal Conductance Fluctuations in Electrolyte-Gated SrTiO3 Nanostructures

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• Electronic subbands in the a-LaAlO${}_3$/KTaO${}_3$ interface revealed by quantum oscillations in high magnetic fields
• Ambipolar suppression of superconductivity by ionic gating in optimally-doped BaFe2(As,P)2 ultrathin films
• Quantized critical supercurrent in SrTiO${}_3$-based quantum point contacts
• Orientation-dependent electric transport and band filling in hole co-doped epitaxial diamond films
• Two-dimensional hole transport in ion-gated diamond surfaces: A brief review
• Evaluation of Disorder Introduced by Electrolyte Gating through Transport Measurements in Graphene
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• Doping controlled Fano resonance in bilayer 1T${}^{\prime }$-ReS${}_2$: Raman experiments and first-principles theoretical analysis
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• Self-aligned local electrolyte gating of 2D materials with nanoscale resolution
• Anomalous metallic phase in molybdenum disulphide induced via gate-driven organic ion intercalation
• Strong band-filling-dependence of the scattering lifetime in gated MoS2 nanolayers induced by the opening of intervalley scattering channels
• Reversible Tuning of Superconductivity in Ion-Gated NbN Ultrathin Films by Self-Encapsulation with a High-$\kappa$ Dielectric Layer
• Nanoscale electronic transparency of wafer-scale hexagonal boron nitride
• On the formation of a conducting surface channel by ionic liquid gating of an insulator
• Symmetry induced phonon renormalization in few layers of 2H-MoTe${}_2$ transistors: Raman and first-principles studies
• Controlling Spin-Mixing Conductance in KTaO${}_3$ 2DEGs by Varying Argon-Ion Irradiation Time