Premium
Amorphous phase of GeTe‐based phase‐change memory alloys: Polyvalency of GeTe bonding and polyamorphism
Author(s) -
Kolobov Alexander V.,
Fons Paul,
Krbal Milos,
Tominaga Junji
Publication year - 2012
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201100752
Subject(s) - polyamorphism , amorphous solid , materials science , phase (matter) , phase change memory , condensed matter physics , phase change , crystallography , order (exchange) , chemical physics , nanotechnology , chemistry , thermodynamics , physics , organic chemistry , finance , layer (electronics) , economics
The structure of the amorphous phase of GeTe‐based phase‐change materials is discussed. Comparison of the Ge(4):Te(2) and Ge(3):Te(3) configurations present in the amorphous phase suggests that the former is locally more stable while the latter can lower its energy due to ‘resonance’ interactions in structures within more extended order. We further demonstrate that polyvalency of the GeTe bonds can lead to the formation of negative‐ U defects accounting for the high resistivity of the amorphous phase. Finally, polyamorphysm of the amorphous phase of Ge 2 Sb 2 Te 5 is discussed.