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The Effects of the Electron-Phonon Interaction on the Vibrational Anomalies and Polymorphism in Titanium

Published online by Cambridge University Press:  10 February 2011

J. L. Gavartin  and
D. J. Bacon
J. L. Gavartin
Affiliation:
Department of Materials Science and Engineering, The University of Liverpool, Liverpool, L69 3BX, U.K., j.gavartin@liverpool.ac.uk Institute of Chemical Physics, University of Latvia, LV1586 Riga, Latvia
D. J. Bacon
Affiliation:
Department of Materials Science and Engineering, The University of Liverpool, Liverpool, L69 3BX, U.K., j.gavartin@liverpool.ac.uk
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Abstract

We apply the frozen phonon and molecular dynamics methods within the semiempirical orthogonal tight-binding framework to study the anomalous behaviour of the (0001) optical longitudinal (LO) and transverse (TO) phonons in the low temperature hep phase of Ti, and the ⅔[111]L and ½[110]T1 phonons in the high temperature bec phase. We demonstrate that, in agreement with previous findings in Zr, the anomalous thermal frequency shifts in hep Ti are related to the strong coupling of the electron density of states (DOS) to the particular lattice distortions. The distortions along the bec ⅔[111]L and ½[110]T1 phonons also significantly affect the DOS, resulting in the instability of these modes at low temperatures and triggering the bcc-hep and bcc-ω phase transformations.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 491: Symposium R – Tight Binding Approach to Computational Materials Science , 1997 , 507
Copyright
Copyright © Materials Research Society 1998

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References

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