Eur. Phys. J. Special Topics 222, 1185-1201 (2013)
https://doi.org/10.1140/epjst/e2013-01914-0

Review

Interface transport properties in ion-gated nano-sheets

¹ Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
² CERG, RIKEN, Hirosawa 2-1, Wako 351-0198, Japan

^a e-mail: yejianting@ap.t.u-tokyo.ac.jp

Received: 18 March 2013
Revised: 12 May 2013
Published online: 15 July 2013

Abstract

Recent advances in atomic-scale preparation of ultrathin nano-sheets and efficient field-effect gating mediated by movement of ions have provided a prolific paradigm for creating exotic states at interfaces of a new-type of device called electric-double layer transistors (EDLTs). We present a short review on these liquid/solid interfaces formed on nano-sheets prepared by micro cleaving a bulk layered single crystal, which can be electrostatically doped to a high carrier density of ∼10¹⁴ cm⁻². Atomically flat surfaces prepared on various layered materials allowed ideal transport when they acted as transistor channels after accumulating dense carriers. The unique system combining these two advantages enabled observations of novel transport phenomena showing quantum phase transition of charge and spin states controlled by electric field. Examples include gate-induced metal-insulator transition, opening of new transport channels, and field-induced interface superconductivity, which present a rapidly growing field with emerging opportunities for science and technology.