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Lattice Dynamics and Thermodynamic Properties of Bulk Phases and Monolayers of GaTe and InTe: A Comparison from First‐Principles Calculations
Author(s) -
Bandura Andrei V.,
Kovalenko Alexey V.,
Kuruch Dmitry D.,
Evarestov Robert A.
Publication year - 2021
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202000634
Subject(s) - helmholtz free energy , monolayer , chemistry , brillouin zone , monoclinic crystal system , internal energy , density functional theory , thermodynamics , lattice (music) , computational chemistry , condensed matter physics , molecular physics , crystallography , crystal structure , physics , biochemistry , acoustics
The hybrid density functional theory was used to study the structural, vibrational, and thermodynamic properties of stable and hypothetical bulk GaTe and InTe polymorphs, as well as their monolayer counterparts. Criteria based on the vibrational frequencies have been proposed to distinguish between different monolayer structures. Heat capacity, entropy, and Helmholtz free energy have been calculated by summing the vibrational contributions over the corresponding Brillouin zone. The relative stability of the considered systems has been estimated at different temperatures using the obtained Helmholtz free energy. Both the total energy and the Helmholtz free energy calculations confirmed that a free‐standing monolayer originated from the monoclinic GaTe phase is less stable than its hexagonal analogs. It was also found that the temperature increase favors monolayer formation in the case of GaTe, but prevents it in the case of InTe.