High mobile electron gas at LaAlO3/SrTiO3 heterointerface

2012 ◽  
Vol 1406 ◽  
Author(s):  
Shanshan Su ◽  
Jeong Ho You
Keyword(s):  
Electron Gas ◽  
Polar Optical Phonon ◽  
Dimensional Electron ◽  
Two Dimensional Electron Gas ◽  
Linearized Boltzmann Equation ◽  
The Poisson Equation ◽  
Scattering Center ◽  
Mobile Electron ◽  
Unit Cells ◽  
Dimensional Electron Gas

ABSTRACTWe calculated the mobility of two-dimensional electron gas along an n-type interface in LaAlO3/SrTiO3 heterostructure using the linearized Boltzmann equation. By solving the Schrödinger equation with the Poisson equation self-consistently, it was found that the interface remained non-conducting up to four unit cells of LaAlO3 film. For five or higher unit cells, the interface became conducting due to the significant overlap between the SrTiO3 conduction band and the LaAlO3 valence band. The electron gas was localized within 7 nm from the interface and multi-subbands were occupied. The calculated mobility matches reasonably well with available experimental data. It was found that the mobility is limited by the remote ionic charged layers in LaAlO3 at low temperature. At high temperature, the polar optical phonon was found to be the dominant scattering center.

Conducting Heterointerface of Polar-Nonpolar Band Gap Insulators

2012 ◽  
Author(s):  
Shanshan Su ◽  
Jeong Ho You
Keyword(s):  
Diffusion Model ◽  
Energy Levels ◽  
Electron Gas ◽  
The Self ◽  
Polar Optical Phonon ◽  
Dimensional Electron ◽  
Catastrophe Model ◽  
Linearized Boltzmann Equation ◽  
Dimensional Electron Gas ◽  
Self Consistency

Recently, the heterointerface between two band insulators, LaAlO3 and SrTiO3 has received much attention due to its high conducting behavior. The origin of conducting carriers at the LaAlO3/SrTiO3 heterointerface has been mainly explained by two distinct models: the polar catastrophe model and the atomic inter-diffusion model. The polar catastrophe model is based on a half electron transferred from polar LaAlO3 to nonpolar SrTiO3 to avoid the divergence of electric field without any atomic diffusions. The atomic inter-diffusion model is based on the transfer of dopants from LaAlO3 to SrTiO3 near the interface. However, the origin of the conducting carriers is still under debate and needs to be investigated further. In this study, we have examined the origin of conducting carriers at the LaAlO3/SrTiO3 heterointerface using the self-consistency calculations of Schrödinger equation and Poisson equation. We have studied the LaAlO3/SrTiO3 heterointerfaces with and without atomic diffusions. From the self-consistency calculations, carrier distributions, band structures, energy levels, and wavefunctions have been obtained. It has been found that the majority of electron is localized within a few nm from the interface forming two-dimensional electron gas, and multi-subbands are occupied indicating a multi-channel conducting behavior. We also calculated the electron mobility at the interface using the linearized Boltzmann equation including various scattering mechanisms, such as acoustic phonon, polar optical phonon, and remote charged layers in LaAlO3. The calculated mobility has been compared with available experimental data as a function of temperature and thickness of LaAlO3.

scholarly journals Mobility of a two-dimensional electron gas in the AlGaAs/GaAs heterostructure: simulation and analysis

2019 ◽  
Vol 30 ◽  
pp. 08005
Author(s):  
Vladislav Volcheck ◽  
Viktor Stempitsky
Keyword(s):  
Electron Gas ◽  
High Electron Mobility Transistor ◽  
Mobility Model ◽  
Polar Optical Phonon ◽  
High Electron ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Two Dimensional Electron Gas ◽  
C Language ◽  
Dimensional Electron Gas

At temperatures above 100 K, a two-dimensional electron gas generated at the AlGaAs/GaAs heterointerface can be characterized by the three dominant scattering mechanisms: acoustic deformation potential, polar acoustic phonon and polar optical phonon. An analytical model describing the two-dimensional electron gas mobility controlled by these scattering processes as a function of the electron concentration and the temperature was developed and integrated into a device simulator package using a built-in C language interpreter. The electrical characteristics of a simple AlGaAs/GaAs high electron mobility transistor were simulated using either the derived or a conventional bulk mobility model and the results were compared.

scholarly journals Воздействие механических напряжений на зарядовое состояние межфазной границы в гетероструктурах LaAlO-=SUB=-3-=/SUB=-/(001)SrTiO-=SUB=-3-=/SUB=- c нарушенной стехиометрией

2018 ◽  
Vol 60 (1) ◽  
pp. 171
Author(s):  
Ю.А. Бойков ◽  
И.Т. Серенков ◽  
В.И. Сахаров ◽  
В.А. Данилов
Keyword(s):  
Electron Gas ◽  
High Mobility ◽  
Medium Energy ◽  
Dimensional Electron ◽  
Ion Scattering ◽  
Two Dimensional Electron Gas ◽  
Lanthanum Aluminate ◽  
Unit Cells ◽  
Dimensional Electron Gas ◽  
Medium Energy Ion Scattering

AbstractThe medium-energy ion scattering (MEIS) spectroscopy was used to obtain the data on the structure and stoichiometry of interfaces in LaAlO_3/SrTiO_3 (LAO/STO) heterostructures. The coverage of the LAO/STO heterostructure with a LAO film increased by a factor of almost two as the lanthanum aluminate layer thickness increased from 1 to 6 unit cells. It is shown that the formation of the heterostructure is accompanied by the interchange with Sr ions of the substrate and La ions of the firm. The influence of the oxygen pressure on the formation of the heterostructure has been studied. The conditions required to form nanodimentional interlayer of a quasi-two-dimensional electron gas with high mobility of electrons in the interface region are analyzed.

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