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Temperature and Dynamical Effects on the High‐Pressure Cubic‐Diamond ↔ β‐Tin Phase Transition in Si and Ge
Author(s) -
GaálNagy K.,
Bauer A.,
Schmitt M.,
Karch K.,
Pavone P.,
Strauch D.
Publication year - 1999
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199901)211:1<275::aid-pssb275>3.0.co;2-o
Subject(s) - diamond , tin , density functional theory , phase transition , diamond cubic , perturbation theory (quantum mechanics) , gibbs free energy , condensed matter physics , harmonic , materials science , phase (matter) , local density approximation , thermodynamics , physics , quantum mechanics , metallurgy
The cubic‐diamond ↔ β‐tin phase transition in Si and Ge is studied using modern first‐principles techniques based on density‐functional theory (DFT) without making use of any experimental inputs. The relevant Gibbs energies, G ( p , T ) = U — TS + pV , are obtained in the quasi‐harmonic approximation from static internal energies and free‐energy vibrational contributions in the two different phases, as computed by DFT and density‐functional perturbation theory (DFPT), respectively. Our results show that the combination of the quasi‐harmonic approximation and DFPT provides an efficient tool for the study of finite‐temperature pressure‐induced solid–solid phase transformations.