Pressure-Induced Phase Transitions in Germanium Telluride: Raman Signatures of Anharmonicity and Oxidation

Amit Pawbake, Christophe Bellin, Lorenzo Paulatto, Keevin Béneut, Johan Biscaras, Chandrabhas Narayana, Dattatray J. Late, and Abhay Shukla
Phys. Rev. Lett. 122, 145701 – Published 9 April 2019

Abstract

Pressure-induced phase transitions in GeTe, a prototype phase change material, have been studied to date with diffraction which is not sensitive to anharmonicity-induced dynamical effects. GeTe is also prone to surface oxidation which may compromise surface sensitive measurements. These factors could be responsible for the lack of clarity about the phases and transitions intervening in the phase diagram of GeTe. We have used high-pressure Raman scattering and ab initio pseudopotential density functional calculations to unambiguously establish the high-pressure phase diagram and identify three phases up to 57 GPa, a low-pressure rhombohedral phase, an intermediate pressure cubic phase, and a high-pressure orthorhombic phase. We detect substantial broadening and softening of Raman modes at low pressure and identify the transition regions and possible intermediate phases.

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  • Received 23 January 2019
  • Revised 15 March 2019

DOI:https://doi.org/10.1103/PhysRevLett.122.145701

© 2019 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Amit Pawbake1,*, Christophe Bellin1, Lorenzo Paulatto1, Keevin Béneut1, Johan Biscaras1, Chandrabhas Narayana2, Dattatray J. Late3, and Abhay Shukla1,†

  • 1Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, UMR CNRS 7590, MNHN, IRD UMR 206, 4 Place Jussieu, F-75005 Paris, France
  • 2Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
  • 3Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India

  • *tamitpawbake@gmail.com
  • abhay.shukla@sorbonne-universite.fr

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Issue

Vol. 122, Iss. 14 — 12 April 2019

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