Creating Two-Dimensional Electron Gas in Nonpolar Oxide Interface via Polarization Discontinuity: First-Principles Analysis of CaZrO3/SrTiO3 Heterostructure
arXiv:1508.00598 · doi:10.1021/acsami.5b09107
Abstract
We studied strain-induced polarization and resulting conductivity in the nonpolar/nonpolar CaZrO3/SrTiO3 (CZO/STO) heterostructure (HS) system by means of first-principles electronic structure calculations. By modeling four types of CZO/STO HS-based slab systems, i.e., TiO2/CaO and SrO/ZrO2 interface models with CaO and ZrO2 surface terminations in each model separately, we found that the lattice-mismatch-induced compressive strain leads to a strong polarization in the CZO film, and as the CZO film thickness increases, there exist an insulator-to-metal transition. The polarization direction and critical thickness of the CZO film for forming interfacial metallic states depend on the surface termination of CZO film in both types of interface models. In the TiO2/CaO and SrO/ZrO2 interface models with CaO surface termination, the strong polarization drives the charge transfer from the CZO film to the first few TiO2 layers in the STO substrate, leading to the formation of Two-Dimensional Electron Gas (2DEG) at the interface. In the HS models with ZrO2 surface termination, two polarization domains with opposite directions were formed in the CZO film, which results in the charge transfer from the middle CZO layer to the interface and surface, respectively, leading to the co-existence of the 2DEG on the interface and the Two-Dimensional Hole Gas (2DHG) at the middle CZO layer. These findings open a new avenue to achieve 2DEG (2DHG) in perovskite-based HS systems via polarization discontinuity.
References in corpus (16)
- Magnetic effects at the interface between nonmagnetic oxides
- Why Some Interfaces Cannot be Sharp
- Direct imaging of the coexistence of ferromagnetism and superconductivity at the LaAlO3/SrTiO3 interface
- Coexistence of Magnetic Order and Two-dimensional Superconductivity at LaAlO/SrTiO Interfaces
- Unveiling a two-dimensional electron gas with universal subbands at the surface of SrTiO3
- The role of oxygen vacancies in SrTiO3 at the LaAlO3/SrTiO3 interface
- Creation and control of a two-dimensional electron liquid at the bare SrTiO3 surface
- Metallic and insulating interfaces of amorphous SrTiO3-based oxide heterostructures
- A polarity-induced defect mechanism for conductivity and magnetism at polar-nonpolar oxide interfaces
- Origin of the two-dimensional electron gas at LaAlO3/SrTiO3 interfaces: The role of oxygen vacancies and electronic reconstruction
- Locally enhanced conductivity due to the tetragonal domain structure in LaAlO/SrTiO heterointerfaces
- Nanoscale Phenomena in Oxide Heterostructures
- Room-Temperature Electronically-Controlled Ferromagnetism at the LaAlO3/SrTiO3 Interface
- Creation of high mobility two-dimensional electron gases via strain induced polarization at an otherwise nonpolar complex oxide interface
- Polarization screening and induced carrier density at the interface of LaAlO overlayer on SrTiO (001)
- Observation of strontium segregation in LaAlO/SrTiO and NdGaO/SrTiO oxide heterostructures by X-ray photoemission spectroscopy