TY - JOUR

T1 - Lattice Dynamics and Thermodynamic Properties of Bulk Phases and Monolayers of GaTe and InTe

T2 - A Comparison from First-Principles Calculations

AU - Bandura , Andei

AU - Kovalenko, Alexey

AU - Kuruch , Dmitrii

AU - Evarestov, Robert

N1 - Funding Information: The reported study was funded by the Russian Foundation for Basic Research within the framework of research project no. 20‐03‐00271 and accomplished using the computational facilities of the Resource Center “Computer Center of St. Petersburg State University”. Publisher Copyright: © 2020 Wiley-VCH GmbH Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/1/15

Y1 - 2021/1/15

N2 - 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.

AB - 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.

KW - density functional calculations

KW - monolayers

KW - phonon dispersion

KW - polymorphism

KW - thermodynamics

KW - Density functional calculations

KW - Phonon dispersion

KW - Monolayers

KW - Polymorphism

KW - Thermodynamics

UR - http://www.scopus.com/inward/record.url?scp=85097399692&partnerID=8YFLogxK

U2 - 10.1002/ejic.202000634

DO - 10.1002/ejic.202000634

M3 - Article

AN - SCOPUS:85097399692

VL - 2021

SP - 126

EP - 138

JO - Berichte der deutschen chemischen Gesellschaft

JF - Berichte der deutschen chemischen Gesellschaft

SN - 0365-9496

IS - 2

ER -