Condensed matter, due to its large number of atoms, exhibits a variety of unexpected quantum phases, including superconductivity, magnetism, correlated insulators, and ferroelectrics, and topological phases. In this lecture, I will give a brief review on the electric field (and more broadly voltage) control of quantum matter, with particular interest in two-dimensional van der Waals materials.
Using the device structure, called field effect transistor (FET), we are able to control the carrier density by application of the gate voltage. Since the carrier density is the key parameter for determining the electronic properties of solids, the voltage can be a knob of tuning the electronics state in principle. We have developed a new transistor by replacing the gate insulator with the ionic conductor (and electrical insulator) more than a decade ago. With this device, we found that the accumulated carrier density is one to two orders of magnitude enhanced, and using this device, we first discovered electric field induced superconductivity in an insulator . We called this device electric double layer transistor (EDLT), and have shown that this device is powerful in electric field control of quantum phases in superconductors , Mott insulators , and ferromagnets .
This electrochemical device enables us to further expand the performance of gating devices . One is the layer-by-layer etching to form the monolayer materials . The other is the intercalation of ions into materials . These extensions further push forward the capability of transistor devices for controlling the quantum phases of matter.
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Yoshihiro Iwasa，Professor，Quantum Phase Electronics Center and Department of Applied Physics，The University of Tokyo
Team Leader，RIKEN Center for Emergent Matter Science
PhD in Applied Physics, University of Tokyo, Japan, 1986
Team Leader, RIKEN, 2012-
Professor, University of Tokyo, 2010-
Professor, Tohoku University, 2001
Associate Professor, Japan Advanced Institute for Science and Technology, 1994
Award and Honors
Nishina Memorial Prize, 2019
Honda Frontier Prize, 2015
The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology, 2014
Japan IBM Science Prize, 2004