Zur Darstellung und Struktur von CaMnBi<sub>2</sub> / On the Preparation and Crystal Structure of CaMnBi<sub>2</sub>

Brechtel, Erwin; Cordier, G.; Schäfer, Herbert

doi:10.1515/znb-1980-0102

Cited by 45 publications

(19 citation statements)

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“…1 [32], and SrZnBi 2 [33]. The HfCuSi 2 type structure has variously also been designated as ZrCuSi 2 type [59], CaMnBi 2 type [60], and UCuAs 2 type [61]. All of these structures may be regarded as belonging to a large family of tetragonal structures of which those of PbClF and ThCr 2 Si 2 are probably the best known members.…”

Section: Discussionmentioning

confidence: 99%

Preparation and Crystal Structures of Ternary Rare Earth Silver and Gold Arsenides LnAgAs₂ and LnAuAs₂ with Ln = La–Nd, Sm, Gd, and Tb

Eschen

Jeitschko

2003

Zeitschrift Für Naturforschung B

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The 14 arsenides LnAgAs 2 and LnAuAs 2 (Ln = La-Nd, Sm, Gd, Tb) were prepared by reaction of stoichiometric mixtures of the elemental components at high temperatures and characterized by Xray diffractometry. The silver compounds LaAgAs 2 and CeAgAs 2 and the gold compounds LnAuAs 2 (Ln = Ce-Nd, Sm, Gd, Tb) crystallize with HfCuSi 2 type structure (P4/nmm, Z = 2). Of these, the structures of CeAgAs 2 (a = 408.5(1), c = 1048.2(1) pm, conventional residual R = 0.017 for 261 structure factors and 12 variable parameters) and CeAuAs 2 (a = 411.4(1), c = 1015.3(2) pm, R = 0.030 for 428 F values) were refined from four-circle diffractometer data. The silver compounds LnAgAs 2 (Ln = Pr, Nd, Sm, Gd, Tb) are isotypic with the antimonide SrZnSb 2 (Pnma, Z = 4) as demonstrated by a single-crystal structure refinement of PrAgAs 2 (a = 2107.3(4), b = 401.7(1), c = 407.8(1) pm, R = 0.042 for 746 F values and 26 variables). The gold compound LaAuAs 2 (I4/mmm, Z = 4, a = 416.9(1), c = 2059.5(3) pm, R = 0.038 for 303 F values and 13 variables) was found to be isotypic with the bismuthide SrZnBi 2 , again by a refinement from single-crystal diffractometer data. In the structures of CeAgAs 2 , LaAuAs 2 , and CeAuAs 2 large displacement parameters perpendicular to the four-fold axes were found for one of the two arsenic positions. These structures could also be refined with split positions for these arsenic atoms, which allow for considerable As-As bonding, resulting in a formal charge of −1 for these atoms. Chemical bonding in these compounds can thus be rationalized by a simple model corresponding to the formula Ln +3 T +1 As −1 As −3 (T = Ag, Au), where the superscripts indicate oxidation numbers.

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Section: Discussionmentioning

confidence: 99%

Preparation and Crystal Structures of Ternary Rare Earth Silver and Gold Arsenides LnAgAs₂ and LnAuAs₂ with Ln = La–Nd, Sm, Gd, and Tb

Eschen

Jeitschko

2003

Zeitschrift Für Naturforschung B

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“…1(a)). The MnBi 4 tetrahedrons are less distorted and the lattice is smaller when compared to SrMnBi 2 with I4/mmm space group since Ca has smaller radius than Sr. 17,23 The in-plane resistivity ρ ab (T ) ( Fig. 1(b)) is metallic with a weak anomaly at ∼ 50 K. The resistivity along the c-axis is higher in magnitude than the in-plane resistivity with ρ c (T )/ρ ab (T ) ∼ 10 − 15 below 100 K. In what follows we will only discuss the in-plane MR. An external magnetic field enhances the low-temperature resistivity and the MR ratio MR= (ρ ab (B) − ρ ab (0))/ρ ab (0) reaches 120% at 2 K in 9 T field.…”

Section: 18mentioning

confidence: 99%

Two-dimensional Dirac fermions and quantum magnetoresistance in CaMnBi2

et al. 2012

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We report two dimensional Dirac fermions and quantum magnetoresistance in single crystals of CaMnBi2. The non-zero Berry's phase, small cyclotron resonant mass and first-principle band structure suggest the existence of the Dirac fermions in the Bi square nets. The in-plane transverse magnetoresistance exhibits a crossover at a critical field B * from semiclassical weak-field B 2 dependence to the high-field unsaturated linear magnetoresistance (∼ 120% in 9 T at 2 K) due to the quantum limit of the Dirac fermions. The temperature dependence of B * satisfies quadratic behavior, which is attributed to the splitting of linear energy dispersion in high field. Our results demonstrate the existence of two dimensional Dirac fermions in CaMnBi2 with Bi square nets.

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“…The unit cell information for the band structure calculation is taken from ref. (28). (c) Crystal and electronic structure of ZrSiS.…”

Section: A Brief History Of Square-net Topological Semimetalsmentioning

confidence: 99%

Topological Semimetals in Square-Net Materials

Klemenz

Lei

Schoop

2019

Annu. Rev. Mater. Res.

128

110

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Many materials crystallize in structure types that feature a square-net of atoms. While these compounds can exhibit many different properties, some members of this family are topological materials. Within the square-net-based topological materials, the observed properties are rich, ranging for example from nodal-line semimetals to a bulk halfinteger quantum Hall effect. Hence, the potential for guided design of topological properties is enormous. Here we provide an overview of the crystallographic and electronic properties of these phases and show how they are linked, with the goal of understanding which square-net materials can be topological, and to predict additional examples. We close the review by discussing the experimentally observed electronic properties in this family. 2 Schoop et al. 6 Schoop et al.

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Zur Darstellung und Struktur von CaMnBi₂ / On the Preparation and Crystal Structure of CaMnBi₂

Cited by 45 publications

References 0 publications

Preparation and Crystal Structures of Ternary Rare Earth Silver and Gold Arsenides LnAgAs₂ and LnAuAs₂ with Ln = La–Nd, Sm, Gd, and Tb

Preparation and Crystal Structures of Ternary Rare Earth Silver and Gold Arsenides LnAgAs₂ and LnAuAs₂ with Ln = La–Nd, Sm, Gd, and Tb

Two-dimensional Dirac fermions and quantum magnetoresistance in CaMnBi2

Topological Semimetals in Square-Net Materials

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Zur Darstellung und Struktur von CaMnBi2 / On the Preparation and Crystal Structure of CaMnBi2

Cited by 45 publications

References 0 publications

Preparation and Crystal Structures of Ternary Rare Earth Silver and Gold Arsenides LnAgAs2 and LnAuAs2 with Ln = La–Nd, Sm, Gd, and Tb

Preparation and Crystal Structures of Ternary Rare Earth Silver and Gold Arsenides LnAgAs2 and LnAuAs2 with Ln = La–Nd, Sm, Gd, and Tb

Two-dimensional Dirac fermions and quantum magnetoresistance in CaMnBi2

Topological Semimetals in Square-Net Materials

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Product

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Zur Darstellung und Struktur von CaMnBi₂ / On the Preparation and Crystal Structure of CaMnBi₂

Preparation and Crystal Structures of Ternary Rare Earth Silver and Gold Arsenides LnAgAs₂ and LnAuAs₂ with Ln = La–Nd, Sm, Gd, and Tb

Preparation and Crystal Structures of Ternary Rare Earth Silver and Gold Arsenides LnAgAs₂ and LnAuAs₂ with Ln = La–Nd, Sm, Gd, and Tb