Electronic and Thermoelectric Properties of Li-Based Half-Heusler Alloys: A DFT Study

In this paper, we have studied the electronic, elastic and thermoelectric properties of the half-Heusler LiCrZ (Z = C, N, Si, and P) materials in Type II phase, in this structure the atomic occupations are X (1/2,1/2,1/2), Y (0,0,0) and Z(1/4,1/4,1/4). The ferromagnetic state of Type II structure wa...

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Main Authors: Issaad F., Maafa A., Rozale H., Boukli Hacene M.A., Bouabça A.
Format: Article
Language:English
Published: Sciendo 2020-12-01
Series:Annals of West University of Timisoara: Physics
Subjects:
Online Access:https://doi.org/10.2478/awutp-2020-0006
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author Issaad F.
Maafa A.
Rozale H.
Boukli Hacene M.A.
Bouabça A.
author_facet Issaad F.
Maafa A.
Rozale H.
Boukli Hacene M.A.
Bouabça A.
author_sort Issaad F.
collection DOAJ
description In this paper, we have studied the electronic, elastic and thermoelectric properties of the half-Heusler LiCrZ (Z = C, N, Si, and P) materials in Type II phase, in this structure the atomic occupations are X (1/2,1/2,1/2), Y (0,0,0) and Z(1/4,1/4,1/4). The ferromagnetic state of Type II structure was found to be the most stable phase for all studied alloys. After calculating the elastic constants, we found out that the conditions of mechanical stability were verified only for LiCrSi and LiCrP alloys in Type II phase, at both equilibrium a0 and half metallic ahm lattice constants, which indicates that these two compounds can be synthesized experimentally. We should also mention that the half metallic behavior in Type II structure, for LiCrSi and LiCrP compounds, was obtained by straining the equilibrium lattice constants by 2% and 6%, respectively. At ahm, these two systems were identified to be true half metals due to their complete spin polarization and integer value of total magnetic moment. These last ones have reached 3μB per unit cell when Z = Si, and 4μB when Z = P. Using the mean field approximation (MFA), the Curie temperatures of Type II structure were also determined, where the values are estimated to be 456.2 K and 302.8 K, respectively. Finally, the thermoelectric performance has been explored by the classical Boltzmann theory. At low temperatures, the figure of merit has reached 0.73 and 0.93 for LiCrSi and LiCrP, respectively. The considerable ZT values and all calculated physical properties make these two systems promising candidates for thermoelectric applications.
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spelling doaj.art-36d52e9120a647d4a88ecd212332650d2023-01-02T23:31:49ZengSciendoAnnals of West University of Timisoara: Physics1224-97182020-12-016219510710.2478/awutp-2020-0006awutp-2020-0006Electronic and Thermoelectric Properties of Li-Based Half-Heusler Alloys: A DFT StudyIssaad F.0Maafa A.1Rozale H.2Boukli Hacene M.A.3Bouabça A.4Condensed Matter and sustainable development Laboratory (LMCDD), University of Sidi Bel-Abbes, Sidi Bel-Abbes22000, Algeria.Condensed Matter and sustainable development Laboratory (LMCDD), University of Sidi Bel-Abbes, Sidi Bel-Abbes22000, Algeria.Condensed Matter and sustainable development Laboratory (LMCDD), University of Sidi Bel-Abbes, Sidi Bel-Abbes22000, Algeria.Condensed Matter and sustainable development Laboratory (LMCDD), University of Sidi Bel-Abbes, Sidi Bel-Abbes22000, Algeria.Condensed Matter and sustainable development Laboratory (LMCDD), University of Sidi Bel-Abbes, Sidi Bel-Abbes22000, Algeria.In this paper, we have studied the electronic, elastic and thermoelectric properties of the half-Heusler LiCrZ (Z = C, N, Si, and P) materials in Type II phase, in this structure the atomic occupations are X (1/2,1/2,1/2), Y (0,0,0) and Z(1/4,1/4,1/4). The ferromagnetic state of Type II structure was found to be the most stable phase for all studied alloys. After calculating the elastic constants, we found out that the conditions of mechanical stability were verified only for LiCrSi and LiCrP alloys in Type II phase, at both equilibrium a0 and half metallic ahm lattice constants, which indicates that these two compounds can be synthesized experimentally. We should also mention that the half metallic behavior in Type II structure, for LiCrSi and LiCrP compounds, was obtained by straining the equilibrium lattice constants by 2% and 6%, respectively. At ahm, these two systems were identified to be true half metals due to their complete spin polarization and integer value of total magnetic moment. These last ones have reached 3μB per unit cell when Z = Si, and 4μB when Z = P. Using the mean field approximation (MFA), the Curie temperatures of Type II structure were also determined, where the values are estimated to be 456.2 K and 302.8 K, respectively. Finally, the thermoelectric performance has been explored by the classical Boltzmann theory. At low temperatures, the figure of merit has reached 0.73 and 0.93 for LiCrSi and LiCrP, respectively. The considerable ZT values and all calculated physical properties make these two systems promising candidates for thermoelectric applications.https://doi.org/10.2478/awutp-2020-0006li-based half-heusler compoundsdftelastic propertieselectrical conductivity
spellingShingle Issaad F.
Maafa A.
Rozale H.
Boukli Hacene M.A.
Bouabça A.
Electronic and Thermoelectric Properties of Li-Based Half-Heusler Alloys: A DFT Study
Annals of West University of Timisoara: Physics
li-based half-heusler compounds
dft
elastic properties
electrical conductivity
title Electronic and Thermoelectric Properties of Li-Based Half-Heusler Alloys: A DFT Study
title_full Electronic and Thermoelectric Properties of Li-Based Half-Heusler Alloys: A DFT Study
title_fullStr Electronic and Thermoelectric Properties of Li-Based Half-Heusler Alloys: A DFT Study
title_full_unstemmed Electronic and Thermoelectric Properties of Li-Based Half-Heusler Alloys: A DFT Study
title_short Electronic and Thermoelectric Properties of Li-Based Half-Heusler Alloys: A DFT Study
title_sort electronic and thermoelectric properties of li based half heusler alloys a dft study
topic li-based half-heusler compounds
dft
elastic properties
electrical conductivity
url https://doi.org/10.2478/awutp-2020-0006
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AT maafaa electronicandthermoelectricpropertiesoflibasedhalfheusleralloysadftstudy
AT rozaleh electronicandthermoelectricpropertiesoflibasedhalfheusleralloysadftstudy
AT bouklihacenema electronicandthermoelectricpropertiesoflibasedhalfheusleralloysadftstudy
AT bouabcaa electronicandthermoelectricpropertiesoflibasedhalfheusleralloysadftstudy