Crystal Growth of the Nowotny Chimney Ladder Phase Fe<sub>2</sub>Ge<sub>3</sub>: Exploring New Fe-Based Narrow-Gap Semiconductor with Promising Thermoelectric Performance

Verchenko, Valeriy Yu.; Wei, Zheng; Tsirlin, Alexander A.; Callaert, Carolien; Jesche, Anton; Hadermann, Joke; Dikarev, Evgeny V.; Shevelkov, Аndrei V.

doi:10.1021/acs.chemmater.7b03300

Cited by 31 publications

(22 citation statements)

References 49 publications

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“…Such anisotropic peak broadening was taken into account in the refinement procedure using the Stephens method[25]. This anisotropic peak broadening is consistent with the high defect concentration evidenced by TEM on the [Ge] subsystem[17]. Similar observations have also been reported in…”

supporting

confidence: 76%

Crystal structure and high temperature X-ray diffraction study of thermoelectric chimney-ladder FeGe (γ ≈ 1.52)

Tonquesse

Hassam

Michiue

et al. 2020

Journal of Alloys and Compounds

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The crystal structure of Nowotny chimney-ladder phase FeGe γ with γ ≈ 1.52 was studied by X-ray diffractometry from 300 K to 850 K. The diffraction patterns were fitted by Rietveld refinement considering an incommensurate composite crystal structure. The refined crystal structure of FeGe γ is described in details and compared to MnSi γ , a thermoelectric material with γ ≈ 1.74. The lattice parameters a, c Fe and c Ge were found to increase with the temperature following a polynomial law, while the modulation vector component γ remained constant up to the peritectoid decomposition into FeGe and FeGe 2 . Within the temperature range considered, the linear and volumetric thermal expansion parameters increased from about 3×10 −6 K −1 to 10×10 −6 K −1 and from 9.6×10 −6

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supporting

confidence: 76%

Crystal structure and high temperature X-ray diffraction study of thermoelectric chimney-ladder FeGe (γ ≈ 1.52)

Tonquesse

Hassam

Michiue

et al. 2020

Journal of Alloys and Compounds

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“…26) Furthermore, the compound had incommensurate NCL structure, where lattice parameter of crystal structures along c-axis is changed by shrinking the helix period of the E (= Ge) atoms due to compositional modulation. [26][27][28] The 29,30) which is lower than some NCL phase compounds such as MnSi γ [18][19][20][21] and VGe γ . 23) Moreover, electronic structure of the composition Fe 2 Ge 3 was calculated.…”

Section: Introductionmentioning

confidence: 91%

“…Fe 2 Ge 3 has a narrow band gap of ∼0.2 eV and the steep density of states near band edges, which leads to large Seebeck coefficient. 29,30) These features brought the high ZT value of 0.57 in FeGe γ . 29) As mentioned above, we are proposing the new approach: the shortening of both v g and τ by nanostructuring of material with complex crystal structure.…”

Section: Introductionmentioning

confidence: 99%

Growth of epitaxial FeGe_γ nanocrystals with incommensurate Nowotny chimney-ladder phase on Si substrate

Terada¹,

Ishibe²,

Watanabe³

et al. 2018

Jpn. J. Appl. Phys.

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We developed the growth technique of epitaxial nanocrystals of FeGe γ (γ > 1.52), a recently-found new crystal with incommensurate Nowotny chimney-ladder phase, on Si(001) substrates. This bulk material is promising for thermoelectric application, and now their films and nanostructures are expected to be fabricated. However, it was difficult to grow single phase epitaxial FeGe γ directly on Si substrates by conventional growth method. On the other hand, we successfully formed almost single phase epitaxial FeGe γ nanocrystals on Si substrates covered with ultrathin SiO 2 films with nanowindows. Reflection high energy electron diffraction indicated that the nanocrystals had the Nowotny chimney-ladder structure, the lattice constants of which were approximately consistent with those of FeGe γ bulk. This indicated strain relaxation in nanocrystals due to the hemispherical shape. This will open a road to realize high performance thermoelectric nanomaterials on Si substrates.

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“…NCL phases are widely known and crystallize in more than 10 structure types [9][10][11][12][13][14][15][16]. Despite the variety of the crystal structures, they all have common dominant features.…”

Section: Introductionmentioning

confidence: 99%

“…For many such compounds, the corresponding approximant structures have been proposed. Thus, single crystals of Fe 2 Ge 3 possess a precise composition and commensurate structure, while a polycrystalline sample is characterized by a complex incommensurate crystal structure [10][11][12]. In addition, helices can be formed by more than one element.…”

Section: Introductionmentioning

confidence: 99%

Nowotny Chimney Ladder Phases with Group 5 Metals: Crystal and Electronic Structure and Relations to the CrSi2 Structure Type

et al. 2020

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Nowotny chimney ladder (NCL) phases are intermetallic compounds formed by transition metals and metals of groups 13 and 14. This family can be expanded by combining two p-elements from different groups with those transition metals, for which the corresponding binary NCL phases are unknown. In this paper, we present three new compounds in the V-Al-Ge, Nb-Al-Ge, and Nb-Ga-Ge systems related to the TiSi2 structure type (Sp. Gr. Fddd) obtained with the standard ampule technique. The crystal structures of the new compounds were determined using synchrotron powder X-ray diffraction data. A transition to the CrSi2 structure type was detected upon changing the composition from VAl0.72(2)Ge1.28(2) to VAl1.534(3)Ge0.466(3). According to the 18–n rule, all the compounds are metallic conductors, which was supported by the electronic structure calculations. It was shown that the expected energy gap located above the Fermi level in the vanadium-based NCL compound collapsed into a pseudogap upon the replacement of V by Nb.

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Crystal Growth of the Nowotny Chimney Ladder Phase Fe₂Ge₃: Exploring New Fe-Based Narrow-Gap Semiconductor with Promising Thermoelectric Performance

Abstract: Crystal grow th of the Now otny chimney ladder phase: exploring new Fe-based narrow -gap semiconductor w ith promising thermoelectric performance Chemistry of materials -

Cited by 31 publications

References 49 publications

Crystal structure and high temperature X-ray diffraction study of thermoelectric chimney-ladder FeGe (γ ≈ 1.52)

Crystal structure and high temperature X-ray diffraction study of thermoelectric chimney-ladder FeGe (γ ≈ 1.52)

Growth of epitaxial FeGe_γ nanocrystals with incommensurate Nowotny chimney-ladder phase on Si substrate

Nowotny Chimney Ladder Phases with Group 5 Metals: Crystal and Electronic Structure and Relations to the CrSi2 Structure Type

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Crystal Growth of the Nowotny Chimney Ladder Phase Fe2Ge3: Exploring New Fe-Based Narrow-Gap Semiconductor with Promising Thermoelectric Performance

Abstract: Crystal grow th of the Now otny chimney ladder phase: exploring new Fe-based narrow -gap semiconductor w ith promising thermoelectric performance Chemistry of materials -

Cited by 31 publications

References 49 publications

Crystal structure and high temperature X-ray diffraction study of thermoelectric chimney-ladder FeGe (γ ≈ 1.52)

Crystal structure and high temperature X-ray diffraction study of thermoelectric chimney-ladder FeGe (γ ≈ 1.52)

Growth of epitaxial FeGeγ nanocrystals with incommensurate Nowotny chimney-ladder phase on Si substrate

Nowotny Chimney Ladder Phases with Group 5 Metals: Crystal and Electronic Structure and Relations to the CrSi2 Structure Type

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Crystal Growth of the Nowotny Chimney Ladder Phase Fe₂Ge₃: Exploring New Fe-Based Narrow-Gap Semiconductor with Promising Thermoelectric Performance

Growth of epitaxial FeGe_γ nanocrystals with incommensurate Nowotny chimney-ladder phase on Si substrate