First-principles calculations of structural, elastic, electronic and transport properties of vanadium-doped zirconium lead carbide max phase

First-principles calculations have been used to systematically investigate the structural, electronic, elastic, thermodynamic, and transport properties of Zr2PbC MAX phase and its alloys. The V-based alloys (VxZri-x)2PbC, 0 < x < 1 were synthesized by substituting V on the M-site of the MAX ph...

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Main Author:	Ahams, Summanuwa Timothy
Format:	Thesis
Language:	English
Published:	2022
Subjects:	QC Physics
Online Access:	http://eprints.utm.my/id/eprint/101783/1/SummanuwaTimothyAhamspsPFS2022.pdf.pdf
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spelling	my-utm-ep.1017832023-07-09T02:17:47Z First-principles calculations of structural, elastic, electronic and transport properties of vanadium-doped zirconium lead carbide max phase 2022 Ahams, Summanuwa Timothy QC Physics First-principles calculations have been used to systematically investigate the structural, electronic, elastic, thermodynamic, and transport properties of Zr2PbC MAX phase and its alloys. The V-based alloys (VxZri-x)2PbC, 0 < x < 1 were synthesized by substituting V on the M-site of the MAX phase at a concentration of 0.25, 0.50, 0.75, and 1.00 respectively. Within the density functional theory (DFT), density functional perturbation theory (DFPT), and Boltzmann transport theory, the generalized gradient approximation (GGA: PBE, PBEsol, PW91), the local density approximation (LDA: PZ) exchange-correlation functionals, and the plane-wave pseudopotential method were used. The examined materials crystallized into a hexagonal shape of space group P63/mmc in relaxed and optimized configurations. The calculated electronic bands and density of states show that the studied MAX phases are conductors. The elastic constants show that all studied materials are mechanically stable based on the Born stability criteria for hexagonal crystals, and structurally stable based on the total minimum energy of the relaxed structures. The 100 % replacement of the Zr atoms shows a significant increase in the Seebeck coefficient and the thermoelectric figure of merit of the terminal MAX phase (V2PbC). Structurally all the studied materials are hard, brittle, and of high directional anisotropy. Calculated properties have been compared with available experimental data and are in good agreement. All four alloys show a significant increase in the electronic, elastic and thermodynamic properties with a decrease in the lattice parameters as the V concentration increases. The terminal alloy V2PbC has a lower total energy compared to the Zr2PbC. The transport properties have been calculated in a temperature range of 200 to 800 K by applying GGA (PBE). For the material at 800 K, a rapid decrease in the thermal conductivity with a slow decrease in electrical conductivity leads to an increase in the figure of merit. 2022 Thesis http://eprints.utm.my/id/eprint/101783/ http://eprints.utm.my/id/eprint/101783/1/SummanuwaTimothyAhamspsPFS2022.pdf.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:147912 phd doctoral Universiti Teknologi Malaysia Faculty of Science
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	QC Physics
spellingShingle	QC Physics Ahams, Summanuwa Timothy First-principles calculations of structural, elastic, electronic and transport properties of vanadium-doped zirconium lead carbide max phase
description	First-principles calculations have been used to systematically investigate the structural, electronic, elastic, thermodynamic, and transport properties of Zr2PbC MAX phase and its alloys. The V-based alloys (VxZri-x)2PbC, 0 < x < 1 were synthesized by substituting V on the M-site of the MAX phase at a concentration of 0.25, 0.50, 0.75, and 1.00 respectively. Within the density functional theory (DFT), density functional perturbation theory (DFPT), and Boltzmann transport theory, the generalized gradient approximation (GGA: PBE, PBEsol, PW91), the local density approximation (LDA: PZ) exchange-correlation functionals, and the plane-wave pseudopotential method were used. The examined materials crystallized into a hexagonal shape of space group P63/mmc in relaxed and optimized configurations. The calculated electronic bands and density of states show that the studied MAX phases are conductors. The elastic constants show that all studied materials are mechanically stable based on the Born stability criteria for hexagonal crystals, and structurally stable based on the total minimum energy of the relaxed structures. The 100 % replacement of the Zr atoms shows a significant increase in the Seebeck coefficient and the thermoelectric figure of merit of the terminal MAX phase (V2PbC). Structurally all the studied materials are hard, brittle, and of high directional anisotropy. Calculated properties have been compared with available experimental data and are in good agreement. All four alloys show a significant increase in the electronic, elastic and thermodynamic properties with a decrease in the lattice parameters as the V concentration increases. The terminal alloy V2PbC has a lower total energy compared to the Zr2PbC. The transport properties have been calculated in a temperature range of 200 to 800 K by applying GGA (PBE). For the material at 800 K, a rapid decrease in the thermal conductivity with a slow decrease in electrical conductivity leads to an increase in the figure of merit.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Ahams, Summanuwa Timothy
author_facet	Ahams, Summanuwa Timothy
author_sort	Ahams, Summanuwa Timothy
title	First-principles calculations of structural, elastic, electronic and transport properties of vanadium-doped zirconium lead carbide max phase
title_short	First-principles calculations of structural, elastic, electronic and transport properties of vanadium-doped zirconium lead carbide max phase
title_full	First-principles calculations of structural, elastic, electronic and transport properties of vanadium-doped zirconium lead carbide max phase
title_fullStr	First-principles calculations of structural, elastic, electronic and transport properties of vanadium-doped zirconium lead carbide max phase
title_full_unstemmed	First-principles calculations of structural, elastic, electronic and transport properties of vanadium-doped zirconium lead carbide max phase
title_sort	first-principles calculations of structural, elastic, electronic and transport properties of vanadium-doped zirconium lead carbide max phase
granting_institution	Universiti Teknologi Malaysia
granting_department	Faculty of Science
publishDate	2022
url	http://eprints.utm.my/id/eprint/101783/1/SummanuwaTimothyAhamspsPFS2022.pdf.pdf
_version_	1776100770535440384

First-principles calculations of structural, elastic, electronic and transport properties of vanadium-doped zirconium lead carbide max phase

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