On the question of commensurability – The Nowotny chimney-ladder structures revisited

Rohrer, Franziska E.; Lind, Hanna; Eriksson, Lars; Larsson, Ann‐Kristin; Lidin, Sven

doi:10.1524/zkri.2000.215.11.650

Cited by 17 publications

(10 citation statements)

References 20 publications

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“…In the earlier mentioned domains, where the q -vector has nonzero a * and b * components, the tetragonal symmetry is necessarily broken. − The tetragonal model deduced below for the single crystals was used for generating the calculated image shown as an inset in Figure e. It shows a good agreement for the basic feature seen in the image.…”

Section: Results and Discussionmentioning

confidence: 88%

“…Such deviations from the stoichiometric composition with γ = 1.5 are unfortunately too small to confirm with EDX analysis, as they are beyond the precision of EDX on a TEM instrument. In summary, two main phases appear in the polycrystalline sample of FeGe γ (γ ≈ 1.5): (i) an orthorhombic commensurate structure with cell parameters a ≈ 5.45 Å, b ≈ 5.6 Å, and c ≈ 8.95 Å and space group Pcc 2 or Pccm ; and (ii) an incommensurate phase that can be indexed with the superspace group used in literature for NCLs, , that is, I 4 1 / amd (00γ)00 ss , and with approximate cell parameters a ≈ 5.6 Å, c ≈ 4.6 Å, and variable q , most frequently q = 0.49(3) c *. The patterns agree with the patterns characteristic of NCLs; however, the simultaneous presence of a commensurate and several slightly different incommensurate phases, and minor amounts of admixtures hinder fitting of the PXRD pattern of FeGe γ for γ = 1.5.…”

Section: Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

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

et al. 2017

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Section: Results and Discussionmentioning

confidence: 88%

Section: Results and Discussionmentioning

confidence: 99%

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

et al. 2017

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“…By removing those which have too high sterical pressure, the actual NCL structure is found 28 . Naturally, this arrangement leaves considerable room for incommensuration between the Ru and Sn sublattices and the nucleation of defects in the Sn structure 27,45,46 . Now let us discuss the magnetic field dependence of the MR (Fig.…”

Section: Discussionmentioning

confidence: 99%

Linear nonsaturating magnetoresistance in the Nowotny chimney ladder compound Ru$_2$Sn$_3$

Wu,

Barrena,

Mompeán

et al. 2020

Preprint

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We present magnetoresistivity measurements in high-quality single crystals of the Nowotny chimney ladder compound Ru2Sn3. We find a linear and nonsaturating magnetoresistance up to 20 T. The magnetoresistance changes with the magnetic field orientation at small magnetic fields, from a positive to a negative curvature. Above 5 T, the magnetoresistance shows no sign of saturation up to 20 T for any measured angle. The shape of the anisotropy in the magnetoresistance remains when increasing temperature and Kohler's rule is obeyed. We associate the linear and nonsaturating magnetoresistance to a small Fermi surface with hot spots, possibly formed as a consequence of the structural transition. We discuss the relevance of electron-electron interactions under magnetic fields and aspects of the topologically nontrivial properties expected in Ru2Sn3.

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“…These are solid state compounds that host two or more sublattices that are mutually incommensurate and that may be describes as two crystal structures that interpenetrate and modulate each other. Examples of such compounds are canizzerite, Pb 46 Bi 54 S 127 , a mineral with crystal faces that do not adhere to simple rational indices, and the family of Nowotny chimney ladder phases. , Thanks to monumental efforts, these structures were solved and to some extent understood in terms of periodic crystallography, and their special nature was appreciated, but the full elucidation of their particulars had to wait for the treatment using methods of aperiodic crystallography. − Intermetallic compounds seem to be particularly prone to incommensurability, and a recent review presents some interesting figures. There are 21 primitive tetragonal structure types with more than 100 atoms in the unit cell reported in Pearson’s handbook, and out of these, 11 are composite and an additional two are modulated.…”

Section: Introductionmentioning

confidence: 99%

In Situ Synthesis and Single Crystal Synchrotron X-ray Diffraction Study of ht-Sn₃Sb₂: An Example of How Complex Modulated Structures Are Becoming Generally Accessible

Lidin

Folkers

2018

Acc. Chem. Res.

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Recent developments in X-ray sources and detectors and the parallel development of software for nonstandard crystallography has made analysis of very complex structural problems accessible to nonexperts. Here, we report the successful solution of the structure of ht-SnSb, an analysis that presents several challenges but that is still manageable in a relatively straightforward way. This compound exists only in a narrow temperature regime and undergoes an unquenchable phase transformation on cooling to room temperature; it contains two elements with close to identical scattering factors, and the structure is incommensurately modulated with four symmetry dependent modulation wave vectors. In this study, an attempt was first made to synthesize the title compound by in-house crystal growth in the stability region of ht-SnSb, followed by cooling to room temperature. This is known to produce mutiply twinned stistaite and elemental tin, and this sample, freshly prepared, was then reheated in situ at the single crystal materials beamline Crystal at the synchrotron Soleil. This method was unsuccessful as reheating the sample led to loss of Sn from stistaite as revealed by a change in the measured modulation wave vector. The compound was instead successfully synthesized in situ at the beamline by the topochemical reaction of single crystalline stistaite and liquid tin. A well-formed crystal of stistaite was enclosed in a quartz capillary together with a large excess of tin and heated above the melting point of tin but below the melting point of ht-SnSb. The structure was probed by sychrotron X-ray diffraction using a wavelength close to the absorption edge of Sn to maximize elemental contrast. In the diffraction patterns, first order satellites were observed, making the structure of ht-SnSb incommensurately modulated. Further analysis exposes four q-vectors running along the body diagonals of the cubic unit cell (q' = α α α, q' = -α α -α, q' = -α -α α, q' = α -α -α). To facilitate the analysis, the q vectors were instead treated as axial (q = α 0 0, q = 0 α 0, q = 0 0 α) and an F-type extinction condition for satellites was introduced so that only reflections with hklmnp, mnp all odd or all even, were considered. Further, the modulation functions F(q) were set to zero, and only modulation functions of the type F(q') were refined. The final model uses the four modulation functions, F(q'), F(q'), F(q'), and F(q'), to model occupancy Sn/Sb and positional modulation. The model shows a structure that comprises small NaCl type clusters, typically 7 × 7 × 7 atoms in extension, interspersed between single layers of elemental tin. The terminating layers of tin are slightly puckered, emulating an incipient deformation toward the structure of the layers perpendicular to the [001] direction in elemental tin. It is notable that this model is complementary to that of stistaite. In stistaite, two-dimensionally infinite slabs of rock salt are interspersed between layers of antimony along the trigonal [001] direction, so that the terminatin...

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On the question of commensurability – The Nowotny chimney-ladder structures revisited

Cited by 17 publications

References 20 publications

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

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

Linear nonsaturating magnetoresistance in the Nowotny chimney ladder compound Ru$_2$Sn$_3$

In Situ Synthesis and Single Crystal Synchrotron X-ray Diffraction Study of ht-Sn₃Sb₂: An Example of How Complex Modulated Structures Are Becoming Generally Accessible

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On the question of commensurability – The Nowotny chimney-ladder structures revisited

Cited by 17 publications

References 20 publications

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

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

Linear nonsaturating magnetoresistance in the Nowotny chimney ladder compound Ru$_2$Sn$_3$

In Situ Synthesis and Single Crystal Synchrotron X-ray Diffraction Study of ht-Sn3Sb2: An Example of How Complex Modulated Structures Are Becoming Generally Accessible

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

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

In Situ Synthesis and Single Crystal Synchrotron X-ray Diffraction Study of ht-Sn₃Sb₂: An Example of How Complex Modulated Structures Are Becoming Generally Accessible