Soft phonon mode dynamics in Aurivillius-type structures

Deepam Maurya, Ali Charkhesht, Sanjeev K. Nayak, Fu-Chang Sun, Deepu George, Abhijit Pramanick, Min-Gyu Kang, Hyun-Cheol Song, Marshall M. Alexander, Djamila Lou, Giti A. Khodaparast, S. P. Alpay, N. Q. Vinh, and Shashank Priya
Phys. Rev. B 96, 134114 – Published 18 October 2017
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Abstract

We report the dynamics of soft phonon modes and their role toward various structural transformations in Aurivillius materials by employing terahertz frequency-domain spectroscopy, atomic pair distribution function analysis, and first-principles calculations. We have chosen Bi4Ti3O12 as a model system and identified soft phonon modes associated with the paraelectric tetragonal to the ferroelectric monoclinic transition. Three soft phonon modes have been discovered that exhibit a strong temperature dependence. We have determined that the anharmonicity in Bi-O bonds plays a significant role in phonon softening, and that Bi cations play an important role in the emergence of ferroelectricity.

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  • Received 6 September 2016
  • Revised 14 September 2017

DOI:https://doi.org/10.1103/PhysRevB.96.134114

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Deepam Maurya1,2, Ali Charkhesht3, Sanjeev K. Nayak4, Fu-Chang Sun4, Deepu George3, Abhijit Pramanick5, Min-Gyu Kang1, Hyun-Cheol Song1,6, Marshall M. Alexander3, Djamila Lou3, Giti A. Khodaparast3, S. P. Alpay4,*, N. Q. Vinh3,†, and Shashank Priya1,2,‡

  • 1Bio-Inspired Materials and Devices Laboratory (BMDL), Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061, USA
  • 2Institute for Critical Technology and Applied Science (ICTAS), Virginia Tech, Blacksburg, Virginia 24061, USA
  • 3Department of Physics and Center of Soft Matter and Biological Physics, Virginia Tech, Blacksburg, Virginia 24061, USA
  • 4Department of Materials Science & Engineering, Department of Physics, Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269-3136, USA
  • 5Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR
  • 6Center for Electronic Materials, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea

  • *Corresponding author: pamir.alpay@uconn.edu
  • Corresponding author: vinh@vt.edu
  • Corresponding author: spriya@vt.edu

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Issue

Vol. 96, Iss. 13 — 1 October 2017

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