First-principles study of electronic structure for the Laves-phase compounds HfFe2 and HfV2

Chang-wen, Zhang; Zhong, Ziyi; Wang, Shaoqing; Li, Hua; Dong, Jianji; Xing, Naisheng; Guo, Yanqun; Li, Wei

doi:10.1016/j.jallcom.2006.11.039

Cited by 27 publications

(12 citation statements)

References 20 publications

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“…This coincides with the density of states at the Fermi level exhibiting 2.5 states/atom eV (see Section 3.3). Furthermore, neighboring V-V atoms indicate an overlap of electron densities representing covalent bonding in agreement with other theoretical studies [13,14,62]. In the region around the impurities, charge transfer and sharing between O-Hf and H-M (M = Hf, V), consistent with ionic and covalent interaction, respectively, is obtained.…”

Section: Effect Of Impurities On the Ground State Stabilitysupporting

confidence: 90%

Temperature and Impurity Induced Stabilization of Cubic HfV2 Laves Phase

et al. 2019

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The stability of cubic HfV2 (Fd3m) was investigated as a function of temperature as well as interstitially solved oxygen and hydrogen using density functional theory. Mechanical and energetic instability of pristine cubic HfV2 is obtained in the ground state at 0 K, which is unexpected as it can readily be synthesized. Combined Debye–Grüneisen and electronic entropy calculations indicate that HfV2 is stabilized with increasing temperature primarily as a result of lattice vibrations. In contrast, temperature-induced mechanical stabilization, considering the Born stability criteria, is achieved due to the electronic entropy. Interstitial incorporation of hydrogen and oxygen into the cubic structure contributes to the energetic and mechanical stabilization in the ground state for impurity concentrations as low as 1 at%, owing to strong ionic/covalent bond formation with the matrix atoms.

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Section: Effect Of Impurities On the Ground State Stabilitysupporting

confidence: 90%

Temperature and Impurity Induced Stabilization of Cubic HfV2 Laves Phase

et al. 2019

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“…Laves phase compounds of Hf 1Àx Ta x Fe 2 have attracted a lot of attention in the past decades due to their interesting magnetic properties, [20][21][22][23][24] electronic properties, 18,19,[25][26][27] and their potential applications in giant magnetoresistance (MR) 28,29 and magnetostrictive transducers. 30 The pseudobinary system Hf 1Àx Ta x Fe 2 crystallizes in the hexagonal MgZn 2 -type structure (C-14 Laves phase, space group P6 3 / mmc) with one Mg site (4f) and two sites for the Zn (2a and 6 h) in the whole concentration range of x.…”

Section: Introductionmentioning

confidence: 99%

Collapse of ferromagnetism in itinerant-electron system: A magnetic, transport properties, and high pressure study of (Hf,Ta)Fe2 compounds

Diop

Kaštil

Isnard

et al. 2014

Journal of Applied Physics

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“…Moreover, based on the interatomic distance between Hf and X, the coupling matrix element  would increase from V to Nb and Ta. 25 The weaker hybridization between V and Hf would also infer a more 'localized' nature of the V induced hybridized states near the conduction band edge, giving rise to the resonant states that increases the electrical resistivity and enhances the thermopower. (2)…”

mentioning

confidence: 99%

High thermoelectric figure of merit by resonant dopant in half-Heusler alloys

Chen

Liu

et al. 2017

AIP Advances

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Half-Heusler alloys have been one of the benchmark high temperature thermoelectric materials owing to their thermal stability and promising figure of merit ZT. Simonson et al. early showed that small amounts of vanadium doped in Hf 0.75 Zr 0.25 NiSn enhanced the Seebeck coefficient and correlated the change with the increased density of states near the Fermi level. We herein report a systematic study on the role of vanadium (V), niobium (Nb), and tantalum (Ta) as prospective resonant dopants in enhancing the ZT of n-type half-Heusler alloys based on Hf 0.6 Zr 0.4 NiSn 0.995 Sb 0.005. The V doping was found to increase the Seebeck coefficient in the temperature range 300-1000 K, consistent with a resonant doping scheme. In contrast, Nb and Ta act as normal n-type dopants, as evident by the systematic decrease in electrical resistivity and Seebeck coefficient. The combination of enhanced Seebeck coefficient due to the presence of V resonant states and the reduced thermal conductivity has led to a state-of-the-art ZT of 1.3 near 850 K in n-type (Hf 0.6 Zr 0.4 ) 0.99 V 0.01 NiSn 0.995 Sb 0.005 alloys .

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First-principles study of electronic structure for the Laves-phase compounds HfFe2 and HfV2

Cited by 27 publications

References 20 publications

Temperature and Impurity Induced Stabilization of Cubic HfV2 Laves Phase

Temperature and Impurity Induced Stabilization of Cubic HfV2 Laves Phase

Collapse of ferromagnetism in itinerant-electron system: A magnetic, transport properties, and high pressure study of (Hf,Ta)Fe2 compounds

High thermoelectric figure of merit by resonant dopant in half-Heusler alloys

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