Spin-polarized Two-dimensional Electron Gas at GdTiO₃/SrTiO₃ Interfaces: Insight from First-principles Calculations

Authors

• J. Betancourt, University of Puerto Rico, San Juan
• Tula R. Paudel, University of Nebraska-LincolnFollow
• Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
• J. P. Velev, University of Puerto Rico, San JuanFollow

ORCID IDs

Tsymbal http://orcid.org/0000-0002-6728-5557

Paudel https://orcid.org/0000-0002-9952-9435

Document Type

Article

Date of this Version

7-14-2017

Citation

Physical Review B (2017) 96: 045113

doi: : 10.1103/PhysRevB.96.045113

Comments

Copyright 2017, American Physical Society. Used by permission

Abstract

Two-dimensional electron gases (2DEGs) at oxide interfaces have been a topic of intensive research due to their high carrier mobility and strong confinement. Additionally, strong correlations in the oxide materials can give rise to new and interesting physics, such as magnetism and metal-insulator transitions at the interface. Using first-principles calculations based on density functional theory, we demonstrate the presence of a highly spin-polarized 2DEG at the interface between the Mott insulator GdTiO₃ and a band insulator SrTiO₃. The strong correlations in the dopant cause ferromagnetic alignment of the interface Ti atoms and result in a fully spin-polarized 2DEG. The 2DEG consists of two types of carriers distinguished by their orbital character. The majority of the interface charge is strongly localized on the Ti d_xy orbitals at the interface and a smaller fraction resides on the delocalized Ti d_xz,yz states.