Electric double-layer transistor using layered iron selenide Mott insulator TlFe1.6Se2

Abstract

A1-xFe2-ySe2 (A = K, Cs, Rb, Tl) are recently discovered iron-based superconductors with critical temperatures (Tc) ranging up to 32 K. Their parent phases have unique properties when compared with other iron-based superconductors; e.g., their crystal structures include ordered Fe vacancies, their normal states are antiferromagnetic (AFM) insulating phases, and they have extremely high Néel transition temperatures. However, control of carrier doping into the parent AFM insulators has been difficult due to their intrinsic phase separation. Here, we fabricated an Fe-vacancy-ordered TlFe1.6Se2 insulating epitaxial film with an atomically flat surface and examined its electrostatic carrier doping using an electric double-layer transistor (EDLT) structure with an ionic liquid gate. The positive gate voltage gave conductance modulation of three orders of magnitude at 25 K, and further induced and manipulated a phase transition; i.e., delocalized carrier generation by electrostatic doping is the origin of the phase transition. This is the first demonstration, to the authors' knowledge, of an EDLT using a Mott insulator iron-selenide channel and opens a way to explore high-Tc superconductivity in iron-based layered materials, where carrier doping by conventional chemical means is difficult.

PNAS Early Edition

References in corpus (18)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Fe-based high temperature superconductivity with Tc=31K bordering an insulating antiferromagnet in (Tl,K)FexSe2 Crystals
• Phase Separation and Magnetic Order in K-doped Iron Selenide Superconductor
• Coexistence of static magnetism and superconductivity in SmFeAsO1-xFx as revealed by muon spin rotation
• Common Crystalline and Magnetic Structure of superconducting A2Fe4Se5
• Observation of Temperature-Induced Crossover to an Orbital-Selective Mott Phase in A${}_x$Fe${}_{2-y}$Se${}_2$ (A=K, Rb) Superconductors
• Orbital-selective Mott Phase in Multiorbital Models for Alkaline Iron Selenides K(1-x)Fe(2-y)Se2
• Electronic identification of the actual parental phase of KxFe2-ySe2 superconductor and its intrinsic mesoscopic phase separation
• Electronic and magnetic phase diagram in K${}_x$Fe${}_{2-y}$Se${}_2$ superconductors
• NMR Study in the Iron-Selenide Rb0.74Fe1.6Se2: Determination of the Superconducting Phase as Iron Vacancy-Free Rb0.3Fe2Se2
• Epitaxial growth of FeSe${}_{0.5}$Te${}_{0.5}$ thin films on CaF${}_2$ substrates with high critical current density
• Electronic structures and magnetic orders of Fe-vacancies ordered ternary iron selenides TlFe${}_{1.5}$Se${}_2$ and AFe${}_{1.5}$Se${}_2$ (A=K, Rb, or Cs)
• Mott transition in Modulated Lattices and Parent Insulator of (K,Tl)yFexSe2 Superconductors
• Superconductivity in the iron selenide KxFe2Se2 (0 <= x <= 1)
• New ternary ThCr2Si2-type iron-selenide superconducting materials: synthesis, properties and simulations
• Spin reorientation in TlFe1.6Se2 with complete vacancy ordering
• Unusual Phase Transitions and Magnetoelastic Coupling in TlFe1.6Se2 Single Crystals
• Evolution of the nuclear and magnetic structures of TlFe1.6Se2 with temperature

Cited by in corpus (11)

• Iron-Based Superconductors: current status of materials and pairing mechanism
• Exploration of new superconductors and functional materials and fabrication of superconducting tapes and wires of iron pnictides
• Electric field-induced superconducting transition of insulating FeSe thin film at 35 K
• A Mott insulator continuously connected to iron pnictide superconductors
• Superconducting Transition Temperature Modulation in NbN via EDL Gating
• Ambipolar suppression of superconductivity by ionic gating in optimally-doped BaFe2(As,P)2 ultrathin films
• Insulator-like behavior coexisting with metallic electronic structure in strained FeSe thin films grown by molecular beam epitaxy
• Particulate Generation on Surface of Iron Selenide Films by Air Exposure
• Zoology of spin and orbital fluctuations in ultrathin oxide films
• Status of Iron Based Superconductors: characteristics and relevant properties for applications
• Layered Topological Antiferromagnetic Metal at Room Temperature -- YbMn${}_2$Ge${}_2$