Dual-Gate Modulation of Carrier Density and Disorder in an Oxide Two-Dimensional Electron System.
Carrier density and disorder are two crucial parameters that control the properties of correlated two-dimensional electron systems. In order to disentangle their individual contributions to quantum phenomena, independent tuning of these two parameters is required. Here, by utilizing a hybrid liquid/solid electric dual-gate geometry acting on the conducting LaAlO3/SrTiO3heterointerface, we obtain an additional degree of freedom to strongly modify the electron confinement profile and thus the strength of interfacial scattering, independent from the carrier density. A dual-gate controlled nonlinear Hall effect is a direct manifestation of this profile, which can be quantitatively understood by a Poisson-Schrödinger sub-band model. In particular, the large nonlinear dielectric response of SrTiO3enables a very wide range of tunable density and disorder, far beyond that for conventional semiconductors. Our study provides a broad framework for understanding various reported phenomena at the LaAlO3/SrTiO3interface.
Geballe Laboratory for Advanced Materials, Stanford University , Stanford, California 94305, United States.
Zhuoyu
Z
Chen
Geballe Laboratory for Advanced Materials, Stanford University , Stanford, California 94305, United States.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
Hongtao
H
Yuan
Geballe Laboratory for Advanced Materials, Stanford University , Stanford, California 94305, United States.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
Yanwu
Y
Xie
Geballe Laboratory for Advanced Materials, Stanford University , Stanford, California 94305, United States.
Di
D
Lu
Geballe Laboratory for Advanced Materials, Stanford University , Stanford, California 94305, United States.
Hisashi
H
Inoue
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
Yasuyuki
Y
Hikita
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.|H.H. Wills Physics Laboratory, University of Bristol , Tyndall Avenue, Bristol BS8 1TL, United Kingdom.
Christopher
C
Bell
Geballe Laboratory for Advanced Materials, Stanford University , Stanford, California 94305, United States.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
Harold Y
HY
Hwang
SrTiO3 dielectric constant; disorder; ionic liquid gating; nonlinear Hall effect; oxide interface; quantum confinement