Model of two-dimensional electron gas formation at ferroelectric interfaces

Abstract

The formation of a two-dimensional electron gas at oxide interfaces as a consequence of polar discontinuities has generated an enormous amount of activity due to the variety of interesting effects it gives rise to. Here we study under what circumstances similar processes can also take place underneath ferroelectric thin films. We use a simple Landau model to demonstrate that in the absence of extrinsic screening mechanisms a monodomain phase can be stabilized in ferroelectric films by means of an electronic reconstruction. Unlike in the LaAlO${}_3$/SrTiO${}_3$ heterostructure, the emergence with thickness of the free charge at the interface is discontinuous. This prediction is confirmed by performing first principles simulations of free standing slabs of PbTiO${}_3$. The model is also used to predict the response of the system to an applied electric field, demonstrating that the two-dimensional electron gas can be switched on and off discontinuously and in a non-volatile fashion. Furthermore, the reversal of the polarization can be used to switch between a two-dimensional electron gas and a two-dimensional hole gas, which should, in principle, have very different transport properties. We discuss the possible formation of polarization domains and how such configuration competes with the spontaneous accumulation of free charge at the interfaces.

19 pages, 10 figures

References in corpus (8)

• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• Fractal dimension and size scaling of domains in thin films of multiferroic BiFeO3
• A polarity-induced defect mechanism for conductivity and magnetism at polar-nonpolar oxide interfaces
• Surface defects and conduction in polar oxide heterostructures
• Hyperferroelectrics: proper ferroelectrics with persistent polarization
• Creation of high mobility two-dimensional electron gases via strain induced polarization at an otherwise nonpolar complex oxide interface
• Universality of the Scaling Law for Ferroic Domains
• Oxide superlattices with alternating p and n interfaces

Cited by in corpus (9)

• Two-dimensional electron gas at the PbTiO${}_3$/SrTiO${}_3$ interface: an ab initio study
• First-principles study of two-dimensional electron and hole gases at the head-to-head and tail-to-tail 180${}^{\circ }$ domain walls in PbTiO${}_3$ ferroelectric thin films
• Electrostatics and domains in ferroelectric superlattices
• Ferroelectric control of spin-polarized two-dimensional electron gas
• Polar morphologies from first principles: PbTiO${}_3$ films on SrTiO${}_3$ substrates and the $p(2\times \Lambda )$ surface reconstruction
• Structural and electronic phenomena at oxyfluoride KTaO${}_3$/K$M$F${}_3$ ($M$ = Zn and Ni) superlattices: Rashba splitting and 2DEG
• Mechanism for Switchability in Electron-Doped Ferroelectric Interfaces
• Interfacial Multiferroics of TiO2/PbTiO3 Heterostructure Driven by Ferroelectric Polarization Discontinuity
• Coupling between tilts and charge carriers at polar-nonpolar perovskite interfaces