Electric double-layer transistor using layered iron selenide Mott insulator TlFe1.6Se2
arXiv:1402.2767 · doi:10.1073/pnas.1318045111
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 (10)
- 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
- Coexistence of static magnetism and superconductivity in SmFeAsO1-xFx as revealed by muon spin rotation
- Observation of Temperature-Induced Crossover to an Orbital-Selective Mott Phase in AFeSe (A=K, Rb) Superconductors
- Orbital-selective Mott Phase in Multiorbital Models for Alkaline Iron Selenides K(1-x)Fe(2-y)Se2
- NMR Study in the Iron-Selenide Rb0.74Fe1.6Se2: Determination of the Superconducting Phase as Iron Vacancy-Free Rb0.3Fe2Se2
- Epitaxial growth of FeSeTe thin films on CaF substrates with high critical current density
- Mott transition in Modulated Lattices and Parent Insulator of (K,Tl)yFexSe2 Superconductors
- Spin reorientation in TlFe1.6Se2 with complete vacancy ordering
- Evolution of the nuclear and magnetic structures of TlFe1.6Se2 with temperature