Pre-melting hcp to bcc Transition in Beryllium by First-Principles Phonon Quasiparticle Approach

ORAL

Abstract

<p style="margin: 0px; text-align: justify; line-height: normal; text-justify: inter-ideograph;"><span style="color:black; font-family:times new roman,serif; font-size:12pt; margin:0px">Beryllium (Be) is an important material with wide applications ranging from aerospace components to x-ray ray equipment. Yet a precise understanding of its phase diagram under extreme conditions remains elusive. We have investigated the phase stability of Be using a recently developed hybrid free energy computation method that accounts for anharmonic effects by invoking phonon quasiparticles. We find that the hcp → bcc transition occurs near the melting curve at 0 < P < 11 GPa with a positive Clapeyron slope of 41(4) K/GPa, which is more consistent with recent experimental measurements. This work also demonstrates the validity of this theoretical framework based on the phonon quasiparticle to study the structural stability and phase transitions in strongly anharmonic materials.</span></p>

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Presenters

  • Dong-Bo Zhang

    College of Nuclear Science and Technology, Beijing Normal University, Beijing Computational Science Research Center, Simulation of Physical Systems Division, Beijing Computational Science Research Center, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China

Authors

  • Dong-Bo Zhang

    College of Nuclear Science and Technology, Beijing Normal University, Beijing Computational Science Research Center, Simulation of Physical Systems Division, Beijing Computational Science Research Center, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China

  • Yong Lu

    Beijing Computational Science Research Center, Beijing Computational Science Research Center, Beijing 100193, China

  • Tao Sun

    Key Laboratory of Computational Geodynamics, , University of Chinese Academy of Sciences, Beijing 100049, China, Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, Key Laboratory of Computational Geodynamics, University of Chinese Academy of Sciences, Beijing 100088 China

  • Peihong Zhang

    Physics, University at Buffalo, Department of Physics, University at Buffalo, State University of New York, 14260, USA, University at Buffalo, The State University of New York

  • Renata Wentzcovitch

    Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory (LDEO), and Applied Physics and Applied Mathematics (APAM), Columbia University in the City o, Department of Applied Physics and Applied Mathematics, Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory, Columbia University, Columbia University, Department of Applied Physics and Applied Mathematics, Columbia University, Applied Physics and Applied Mathematics and Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory, Columbia University, Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA, Department of Applied Physics and Applied Mathematics, Columbia University in the City of New York, 500 W. 120th St., Mudd 200, MC 4701 New York, NY 10027, USA., Department of Applied Physics and Applied Mathematics; Department of Earth and Environmental Sciences and Lamont-Doherty Earth Observatory, Columbia University, 10027, USA