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Phonons of Phase‐Change Materials
Author(s) -
Gaspard Jean-Pierre
Publication year - 2022
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.202200111
Subject(s) - phonon , softening , materials science , condensed matter physics , phase transition , hardening (computing) , covalent bond , phase change , phase (matter) , metal , nanotechnology , thermodynamics , composite material , chemistry , physics , organic chemistry , layer (electronics) , metallurgy
Phase‐change materials (PCMs) undergo a reversible transition from a semiconducting to a metallic state, nicely termed “incipient metal.” This transition is driven by a Peierls distortion. A model of covalent bonding is developed in a tight‐binding scheme that accounts for the drastic evolution of some properties of PCMs, among which the Grüneisen parameter. The original vibrational properties of PCM and related Peierls distorted materials are analyzed. A three‐body covalent interaction describes the PCM properties. It explains the simultaneous softening of the optical phonons and the hardening of the acoustic phonons upon crystallization of the PCMs.