Open AccessОсобенности перколяционной схемы перестройки колебательного спектра сплава с составом для Ga-=SUB=-1-x-=/SUB=-Al-=SUB=-x-=/SUB=-P
Author(s) -
S. P. Kozyrev
Publication year - 2018
Publication title -
fizika tverdogo tela
Language(s) - English
Resource type - Journals
eISSN - 1726-7498
pISSN - 0367-3294
DOI - 10.21883/ftt.2018.04.45693.306
Subject(s) - condensed matter physics , alloy , crystal (programming language) , phonon , crystal structure , band gap , materials science , atom (system on chip) , lattice (music) , density of states , crystallography , physics , chemistry , metallurgy , computer science , acoustics , embedded system , programming language
pecific features of the properties of Ga–P lattice vibrations have been investigated using the percolation model of a mixed Ga_1 – x Al_ x P crystal (alloy) with zero lattice mismatch between binary components of the alloy. In contrast to other two-mode alloy systems, in Ga_1 – x Al_ x P a percolation splitting of δ ~ 13 cm^–1 is observed for the low-frequency mode of GaP-like vibrations. An additional GaP mode (one of the percolation doublet components) split from the fundamental mode is observed for the GaP-rich alloy, which coincides in frequency with the gap corresponding to the zero density of one-phonon states of the GaP crystal. The vibrational spectrum of impurity Al in the GaP crystal has been calculated using the theory of crystal lattice dynamics. Upon substitution of lighter Al for the Ga atom, the calculated spectrum includes, along with the local mode, a singularity near the gap with the zero density of phonon states of the GaP crystal, which coincides with the mode observed experimentally at a frequency of 378 cm^–1 in the Ga_1 – x Al_ x P ( x < 0.4) alloy.