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Title: Optical spectroscopy and band gap analysis of hybrid improper ferroelectric Ca{sub 3}Ti{sub 2}O{sub 7}

Abstract

We bring together optical absorption spectroscopy, photoconductivity, and first principles calculations to reveal the electronic structure of the room temperature ferroelectric Ca{sub 3}Ti{sub 2}O{sub 7}. The 3.94 eV direct gap in Ca{sub 3}Ti{sub 2}O{sub 7} is charge transfer in nature and noticeably higher than that in CaTiO{sub 3} (3.4 eV), a finding that we attribute to dimensional confinement in the n = 2 member of the Ruddlesden-Popper series. While Sr substitution introduces disorder and broadens the gap edge slightly, oxygen deficiency reduces the gap to 3.7 eV and gives rise to a broad tail that persists to much lower energies.

Authors:
;  [1]; ;  [2]; ;  [2];  [3];  [1];  [3]
  1. Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996 (United States)
  2. Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22590657
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 108; Journal Issue: 26; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; ABSORPTION SPECTROSCOPY; CONFINEMENT; ELECTRONIC STRUCTURE; FERROELECTRIC MATERIALS; OXYGEN; PHOTOCONDUCTIVITY; TEMPERATURE RANGE 0273-0400 K

Citation Formats

Cherian, Judy G., Harms, Nathan C., Birol, Turan, Vanderbilt, David, Gao, Bin, Cheong, Sang-Wook, Rutgers Center for Emergent Materials, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, Musfeldt, Janice L., E-mail: musfeldt@utk.edu, and Department of Physics, University of Tennessee, Knoxville, Tennessee 37996. Optical spectroscopy and band gap analysis of hybrid improper ferroelectric Ca{sub 3}Ti{sub 2}O{sub 7}. United States: N. p., 2016. Web. doi:10.1063/1.4954404.
Cherian, Judy G., Harms, Nathan C., Birol, Turan, Vanderbilt, David, Gao, Bin, Cheong, Sang-Wook, Rutgers Center for Emergent Materials, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, Musfeldt, Janice L., E-mail: musfeldt@utk.edu, & Department of Physics, University of Tennessee, Knoxville, Tennessee 37996. Optical spectroscopy and band gap analysis of hybrid improper ferroelectric Ca{sub 3}Ti{sub 2}O{sub 7}. United States. doi:10.1063/1.4954404.
Cherian, Judy G., Harms, Nathan C., Birol, Turan, Vanderbilt, David, Gao, Bin, Cheong, Sang-Wook, Rutgers Center for Emergent Materials, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, Musfeldt, Janice L., E-mail: musfeldt@utk.edu, and Department of Physics, University of Tennessee, Knoxville, Tennessee 37996. Mon . "Optical spectroscopy and band gap analysis of hybrid improper ferroelectric Ca{sub 3}Ti{sub 2}O{sub 7}". United States. doi:10.1063/1.4954404.
@article{osti_22590657,
title = {Optical spectroscopy and band gap analysis of hybrid improper ferroelectric Ca{sub 3}Ti{sub 2}O{sub 7}},
author = {Cherian, Judy G. and Harms, Nathan C. and Birol, Turan and Vanderbilt, David and Gao, Bin and Cheong, Sang-Wook and Rutgers Center for Emergent Materials, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854 and Musfeldt, Janice L., E-mail: musfeldt@utk.edu and Department of Physics, University of Tennessee, Knoxville, Tennessee 37996},
abstractNote = {We bring together optical absorption spectroscopy, photoconductivity, and first principles calculations to reveal the electronic structure of the room temperature ferroelectric Ca{sub 3}Ti{sub 2}O{sub 7}. The 3.94 eV direct gap in Ca{sub 3}Ti{sub 2}O{sub 7} is charge transfer in nature and noticeably higher than that in CaTiO{sub 3} (3.4 eV), a finding that we attribute to dimensional confinement in the n = 2 member of the Ruddlesden-Popper series. While Sr substitution introduces disorder and broadens the gap edge slightly, oxygen deficiency reduces the gap to 3.7 eV and gives rise to a broad tail that persists to much lower energies.},
doi = {10.1063/1.4954404},
journal = {Applied Physics Letters},
number = 26,
volume = 108,
place = {United States},
year = {Mon Jun 27 00:00:00 EDT 2016},
month = {Mon Jun 27 00:00:00 EDT 2016}
}