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Full Record Details
Persistent URL
http://purl.org/net/epubs/work/50390244
Record Status
Checked
Record Id
50390244
Title
Sodium Diffusion and Dynamics in Na2Ti3O7: Neutron Scattering and Ab-initio Simulations
Contributors
R Mittal (STFC Rutherford Appleton Lab.)
,
MK Gupta (STFC Rutherford Appleton Lab.)
,
SK Mishra
,
S Mukhopadhyay (STFC Rutherford Appleton Lab.)
,
M Duc Le (STFC Rutherford Appleton Lab.)
,
R Shukla
,
SN Achary
,
AK Tyagi
,
S Chaplot (STFC Rutherford Appleton Lab.)
Abstract
We have performed quasielastic and inelastic neutron scattering (QENS and INS) measurements from 300 K to 1173 K to investigate the Na-diffusion and underlying host dynamics in Na2Ti3O7. The QENS data show that the Na atoms undergo localized jumps up to 1173 K. The ab-initio molecular dynamics (AIMD) simulations supplement the measurements and show 1-d long-ranged diffusion along the a-axis above 1500 K. The simulations indicate that the occupancy of the interstitial site is critical for long-range diffusion. The nudged-elastic-band (NEB) calculation confirmed that the activation energy barrier is lowest for diffusion along the a-axis. In the experimental phonon spectra the peaks at 10 and 14 meV are dominated by Na dynamics that disappear on warming, suggesting low-energy phonons significantly contribute to large Na vibrational amplitude at elevated temperatures that enhances the Na hopping probability. We have also calculated the mode Gr\"uneisen parameters of the phonons and thereby calculated the volume thermal expansion coefficient, which is found to be in excellent agreement with available experimental data.
Organisation
ISIS
,
ISIS-MARI
,
ISIS-OSIRIS
,
STFC
Keywords
RB1910264
,
RB1868015
Funding Information
Related Research Object(s):
10.5286/ISIS.E.RB1910264
,
10.5286/ISIS.E.RB1868015
,
51330885
Licence Information:
Language
English (EN)
Type
Details
URI(s)
Local file(s)
Year
Preprint
Mater Adv
2021.
https://doi.org/1…550/arXiv.2107.09905
2021
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