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Title: Strain effects on the electronic properties in δ -doped oxide superlattices

We investigated strain effects on the electronic properties of (LaTiO3)1/(SrTiO3)N superlattices using density functional theory. Under biaxial in-plane strain within the range of -5% ≤ ε// ≤ 5%, the dxy orbital electrons are highly localized at the interfaces whereas the dyz and dxz orbital electrons are more distributed in the SrTiO3 (STO) spacer layers. For STO thickness N ≥ 3 unit cells (u.c.), the dxy orbital electrons form two-dimensional (2D) electron gases (2DEGs). The quantized energy levels of the 2DEG are insensitive to the STO spacer thickness, but are strongly dependent on the applied biaxial in-plane strain. As the in-plane strain changes from compressive to tensile, the quantized energy levels of the dxy orbitals decrease thereby creating more states with 2D character. In contrast to the dxy orbital, the dyz and dxz orbitals always have three-dimensional (3D) transport characteristics and their energy levels increase as the strain changes from compressive to tensile. In conclusion, since the charge densities in the dxy orbital and the dyz and dxz orbitals respond to biaxial in-plane strain in an opposite way, the transport dimensionality of the majority carriers can be controlled between 2D and 3D by applying biaxial in-plane strain.
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [2]
  1. Southern Methodist Univ., Dallas, TX (United States). Dept. of Mechanical Engineering
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
Publication Date:
OSTI Identifier:
1185729
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Physics. D, Applied Physics
Additional Journal Information:
Journal Volume: 48; Journal Issue: 8; Journal ID: ISSN 0022-3727
Publisher:
IOP Publishing
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY oxide superlattice; LTO/STO heterostructure; electronic reconstruction