Atomic and electronic structure of the ferroelectric BaTiO{sub 3}/Ge(001) interface

Journal Article · Mon Jun 16 04:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4883883· OSTI ID:22300263

Fredrickson, Kurt D.; Ponath, Patrick; Posadas, Agham B.; McCartney, Martha R.; Smith, David J. ^[1]; Aoki, Toshihiro ^[2]

---

1. Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)
2. LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, Arizona 85287 (United States)

In this study, we demonstrate the epitaxial growth of BaTiO{sub 3} on Ge(001) by molecular beam epitaxy using a thin Zintl template buffer layer. A combination of density functional theory, atomic-resolution electron microscopy and in situ photoemission spectroscopy is used to investigate the electronic properties and atomic structure of the BaTiO{sub 3}/Ge interface. Aberration-corrected scanning transmission electron micrographs reveal that the Ge(001) 2 × 1 surface reconstruction remains intact during the subsequent BaTiO{sub 3} growth, thereby enabling a choice to be made between several theoretically predicted interface structures. The measured valence band offset of 2.7 eV matches well with the theoretical value of 2.5 eV based on the model structure for an in-plane-polarized interface. The agreement between the calculated and measured band offsets, which are highly sensitive to the detailed atomic arrangement, indicates that the most likely BaTiO{sub 3}/Ge(001) interface structure has been identified.

• OSTI ID: 22300263
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 24 Vol. 104; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BARIUM COMPOUNDS
BUFFERS
CRYSTAL GROWTH
DENSITY FUNCTIONAL METHOD
ELECTRON MICROSCOPY
ELECTRONIC STRUCTURE
ELECTRONS
FERROELECTRIC MATERIALS
GERMANIUM
INTERFACES
LAYERS
MOLECULAR BEAM EPITAXY
PHOTOEMISSION
RESOLUTION
SPECTROSCOPY
SURFACES
TITANATES
TRANSMISSION