Improved thermoelectric performance of p-doped half-Heusler Ti0.5Zr0.5CoSb0.5P0.5, Ti0.5Hf0.5CoSb0.5P0.5, and Zr0.5Hf0.5CoSb0.5P0.5 compounds

Li, Congcong; Li, Jia; Mao, Xiujuan; Liu, Ze; Xu, Xiang; Liu, Yang; Teng, Sukai; Yin, Fuxing

doi:10.1088/2053-1591/ab56c8

Cited by 5 publications

(3 citation statements)

References 43 publications

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“…To confirm the stability of the compounds after doping, the phonon dispersion of BaMg 2 Bi 2 , BaMg 2 SbBi, and BaMg 2 Sb 2 are presented in figures 2(a)-(c). Imaginary frequency is not observed in the three phonon spectrum, indicating that their structures are dynamically stable [41]. The acoustic branches of phonon dispersion for the three compounds comprise low frequencies, above which they intersect optical modes.…”

Section: Resultsmentioning

confidence: 87%

Enhancing thermoelectric performance of BaMg₂-based compounds by forming solid solutions and biaxial strain

Li¹,

Wang²,

He³

et al. 2021

J. Phys. D: Appl. Phys.

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Two strategies were proposed to optimize the thermoelectric performance of BaMg 2 (Bi,Sb) through a solid solution method and to tune the crystal field splitting energy of orbital by using first principles calculation and Boltzmann transport theory. The increase in Sb content leads to decreased weight carrier mobility due to the changes in the electronic structure. The lattice thermal conductivity for BaMg 2 SbBi can be as low as 0.45 W m −1 K −1 , which is lower than those of other compounds. The highest ZT of ∼0.88 for BaMg 2 SbBi has been obtained at 750 K with n-type doping carrier concentration of −8.28 × 10 18 cm −3 , indicating that reaching the optimal Sb content (i.e. BaMg 2 SbBi) can make a significant contribution to the maximization of the ZT of n-type BaMg 2 (Bi,Sb) solid solutions. Adjusting the crystal field splitting energy increases the effective mass of density of states, which causes the change in power factor (PF) value and achieves a maximum PF value. When the tensile strain for BaMg 2 Bi 2 , BaMg 2 SbBi, and BaMg 2 Sb 2 is 2%, 2%, and 6%, the ZT value is significantly improved, respectively. Therefore, minimizing crystal field splitting energy is also effective in the optimization of the ZT value.

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Section: Resultsmentioning

confidence: 87%

Enhancing thermoelectric performance of BaMg₂-based compounds by forming solid solutions and biaxial strain

Li¹,

Wang²,

He³

et al. 2021

J. Phys. D: Appl. Phys.

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“…In addition, the energy convergent criterion is 10 −5 eV per unit cell, and the forces on all relaxed atoms are less than 0.001 eV/Å. Phonon dispersion was obtained by using the Phonopy package based on the harmonic second-order interatomic force constants with 2 × 2 × 2 supercell [48]. The TE transport properties are calculated using the Boltzmann transport equation in combination with the relaxation time approximation method, and the relaxation time τ is calculated using the deformation potential theory [49][50][51]: with where C 3D is the 3D elastic constant; a 0 is the equilibrium lattice constant; a = a − a 0 is the change of the lattice constant; E is the total energy of the system; V 0 is the volume of a unit cell; m * is the effective mass of carriers, which can be obtained by calculating the second derivative of the energy of the valence band edge; 0 is the energy of the band edge; ⃗ k is the electron wave vector; E is the deformation potential constant; T is the absolute temperature; k B is the Boltzmann constant, and ħ is the Planck constant.…”

Section: Computational and Theoretical Detailsmentioning

confidence: 99%

Prediction of NbXGe (X = Rh, Ir) half-Heusler semiconducting compounds with promising thermoelectric property using 18-electron rule

Wang

et al. 2021

Appl. Phys. A

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The electronic structure, phonons, and thermoelectric transport characteristics of NbXGe (X = Rh, Ir) half-Heusler compounds have been investigated using the first principles based on density functional theory. These alloys show semiconducting character with 18-valence electrons per unit cell following the Slater-Pauling rule. The band gaps of NbRhGe and NbIrGe are 0.65 and 0.63 eV, respectively. The good thermoelectric properties are achieved by applying lattice strains. NbRhGe obtains the ZT value of 0.87 at 300 K at the strain of − 6% gaining a double enhancement compared with the unstrained case, and NbIrGe obtains the ZT value of 0.74 at 300 K at the strain of 6% gaining a 12% enhancement compared with the unstrained case. Moreover, the NbXGe (X = Rh, Ir) half-Heusler compounds with a special quasi-random structure have been modeled to simulate the inevitable atomic occupation disorder between two sublattices. The maximum ZT values of NbIrGe and NbRhGe with SQS are 1.01 (300 K) and 0.83 (1250 K), respectively, which are higher than their corresponding structure of ordered occupation (0.66 and 0.78, respectively). Our results indicate that NbXGe (X = Rh, Ir) should be good thermoelectric candidate materials.

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“…The single-cell structure can be represented as consisting of four interlocking face-centred cubic sublattices with Wyckoff positions A (0, 0, 0), B (1/4, 1/4, 1/4), C (1/2, 1/2, 1/2), and D (3/4, 3/4, 3/4) within a cell. The chemical formula of a half-Heusler alloy is XYZ; its structure can be discerned to be a full-Heusler alloy X 2 YZ with the X-atom at the B-position (Hg 2 CuTi type) or C-position (Cu 2 MnAl type) removed [14][15][16][17][18]. The thermoelectric properties of half-Heusler alloys have been well researched due to their semiconducting nature, while full-Heusler alloys are also attracting attention in thermoelectric applications, because of their adjustable elements and rich structure.…”

Section: Introductionmentioning

confidence: 99%

Study on Enhancing the Thermoelectric Properties of Ti2CrSn Alloys

Song

Ren

et al. 2021

Metals

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Based on the Hg2CuTi structure, the full-Heusler alloy Ti2CrSn, with a ground state band gap of semiconductor, is a thermoelectric material with potential applications. Through preparing Ti2CrSn1−xAlx (x = 0, 0.05, 0.1, 0.15, 0.2) series bulk materials via arc melting, the effects of the electrical and thermal transport properties of Ti2CrSn series alloys were investigated, and different Al doping on the phase structure, the microscopic morphology, and the thermoelectric properties of Ti2CrSn were examined. The results show that the materials all exhibit characteristics of p-type semiconductors at the temperature range of 323 to 923 K. Al elemental doping can significantly increase the Seebeck coefficient and reduce the thermal conductivity of the materials. Among them, the sample Ti2CrSn0.8Al0.2 obtained a maximum value of 5.03 × 10−3 for the thermoelectric optimal ZT value at 723 K, which is 3.6 times higher than that of Ti2CrSn.

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Improved thermoelectric performance of p-doped half-Heusler Ti_0.5Zr_0.5CoSb_0.5P_0.5, Ti_0.5Hf_0.5CoSb_0.5P_0.5, and Zr_0.5Hf_0.5CoSb_0.5P_0.5 compounds

Cited by 5 publications

References 43 publications

Enhancing thermoelectric performance of BaMg₂-based compounds by forming solid solutions and biaxial strain

Enhancing thermoelectric performance of BaMg₂-based compounds by forming solid solutions and biaxial strain

Prediction of NbXGe (X = Rh, Ir) half-Heusler semiconducting compounds with promising thermoelectric property using 18-electron rule

Study on Enhancing the Thermoelectric Properties of Ti2CrSn Alloys

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Improved thermoelectric performance of p-doped half-Heusler Ti0.5Zr0.5CoSb0.5P0.5, Ti0.5Hf0.5CoSb0.5P0.5, and Zr0.5Hf0.5CoSb0.5P0.5 compounds

Cited by 5 publications

References 43 publications

Enhancing thermoelectric performance of BaMg2-based compounds by forming solid solutions and biaxial strain

Enhancing thermoelectric performance of BaMg2-based compounds by forming solid solutions and biaxial strain

Prediction of NbXGe (X = Rh, Ir) half-Heusler semiconducting compounds with promising thermoelectric property using 18-electron rule

Study on Enhancing the Thermoelectric Properties of Ti2CrSn Alloys

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Improved thermoelectric performance of p-doped half-Heusler Ti_0.5Zr_0.5CoSb_0.5P_0.5, Ti_0.5Hf_0.5CoSb_0.5P_0.5, and Zr_0.5Hf_0.5CoSb_0.5P_0.5 compounds

Enhancing thermoelectric performance of BaMg₂-based compounds by forming solid solutions and biaxial strain

Enhancing thermoelectric performance of BaMg₂-based compounds by forming solid solutions and biaxial strain