Distortion and Peak Broadening in Quasicrystal Diffraction Patterns

Lubensky, T. C.; Socolar, Joshua E. S.; Steinhardt, Paul J.; Bancel, Peter A.; Heiney, Paul A.

doi:10.1103/physrevlett.57.1440

Cited by 256 publications

(86 citation statements)

References 13 publications

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“…It displays precisely the same rotational axes and overall face-centered icosahedral symmetry as natural icosahedrite and low phason strain. This low phason strain is contrary to the typical appearance of metastable quasicrystals grown by rapid quenching from melt, which exhibit phason strain that manifests as diffraction peaks that are broadened and shifted systematically from the ideal icosahedrally symmetric pattern (19,20). The peaks in the powder diffraction pattern, indexed on the basis of six integer indices conventionally used with quasicrystals (3,4), are listed in Table 2 and compared with the corresponding peaks in the isostructural natural icosahedrite Al 63 Cu 24 Fe 13 (5,6).…”

Section: Significancementioning

confidence: 73%

Shock synthesis of quasicrystals with implications for their origin in asteroid collisions

Asimow

Lin

Bindi

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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105

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We designed a plate impact shock recovery experiment to simulate the starting materials and shock conditions associated with the only known natural quasicrystals, in the Khatyrka meteorite. At the boundaries among CuAl 5 , (Mg 0.75 Fe 2+ 0.25 ) 2 SiO 4 olivine, and the stainless steel chamber walls, the recovered specimen contains numerous micron-scale grains of a quasicrystalline phase displaying face-centered icosahedral symmetry and low phason strain. The compositional range of the icosahedral phase is Al 68-73 Fe 11-16 Cu 10-12 Cr 1-4 Ni 1-2 and extends toward higher Al/(Cu+Fe) and Fe/Cu ratios than those reported for natural icosahedrite or for any previously known synthetic quasicrystal in the Al-Cu-Fe system. The shock-induced synthesis demonstrated in this experiment reinforces the evidence that natural quasicrystals formed during a shock event but leaves open the question of whether this synthesis pathway is attributable to the expanded thermodynamic stability range of the quasicrystalline phase at high pressure, to a favorable kinetic pathway that exists under shock conditions, or to both thermodynamic and kinetic factors.icosahedrite | shock metamorphism | alloys | meteorites | quasicrystals Q uasicrystals are solids with rotational symmetries forbidden for crystals (1, 2). Quasicrystals can be synthesized in the laboratory by mixing precise ratios of selected elemental components in the liquid and quenching under strictly controlled conditions ranging from rapid to moderately slow (3, 4). Nonetheless, the finding of two natural quasicrystals (5-8) in the Khatyrka meteorite (9), which displays clear evidence of a shock generated by a high-velocity impact event (10), introduced a dramatic new possible mechanism of quasicrystal formation. Here, we report the results of a shock recovery experiment designed to reproduce some aspects of a collision that may have occurred between extraterrestrial bodies.Icosahedrite is only stable on the liquidus of the Al-Cu-Fe system in a narrow compositional range and only between 700°C and 850°C at ambient pressure (11), but its stability field is enlarged in static high-pressure conditions, where it has been observed in experiments quenched from 1,400°C at 21 GPa (12). The presence of other high-pressure phases (ahrensite and stishovite) (10) associated with shocks, adjacent to icosahedrite and decagonite in the Khatyrka CV3 carbonaceous chondrite, together with the static high-pressure stability of the quasicrystalline phase, are suggestive of an origin during the high-pressure pulse of a shock event. However, there are numerous differences between the static high-pressure, high-temperature conditions studied by Stagno et al. (12) and shock-induced conditions at nominally similar peak (P, T) conditions-including heterogeneous and rapidly time-varying pressure and temperature fields (13,14), typical adiabatic decompression rather than temperature quench at high pressure (15), and hypersonic turbulent shear flows (16)(17)(18). A direct demonstration of synthesis of an ...

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Section: Significancementioning

confidence: 73%

Shock synthesis of quasicrystals with implications for their origin in asteroid collisions

Asimow

Lin

Bindi

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

105

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“…Unless grown under the most carefully controlled conditions, quasicrystals exhibit phason strains (Levine et al, 1985;Lubensky et al, 1986), easily detected as deviations of the dimmer peaks from straight lines when the diffraction pattern is viewed at a glancing angle (Lubensky et al, 1986). The electron diffraction patterns in Fig.…”

Section: Impossiblementioning

confidence: 99%

The quest for forbidden crystals

Bindi¹,

Steinhardt²

2014

Mineral. mag.

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The world of crystallography was forced to reassess its rules about thirty years ago with the introduction of the concept of quasicrystals, solids with rotational symmetries forbidden to crystals, by Levine and Steinhardt (1984) and the discovery of the first examples in the laboratory by Shechtman et al. (1984). Since then, >100 different types of quasicrystals have been synthesized in the laboratory under carefully controlled conditions. The original theory suggested that quasicrystals can be as robust and stable as crystals, perhaps even forming under natural conditions. This thought motivated a decade-long search for a natural quasicrystal, culminating in the discovery of icosahedrite (Al 63 Cu 24 Fe 13 ), an icosahedral quasicrystal found in a museum sample consisting of several typical rock-forming minerals combined with exotic rare metal alloy minerals like khatyrkite and cupalite. Here we briefly recount the extraordinary story of the search and discovery of the first natural quasicrystal.

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“…Quasicrystals made by rapid quenching and/or embedded in a matrix of another phase generically exhibit easily detectable phason strains (Levine et al 1985, Lubensky et al 1986.…”

Section: Too Perfect?mentioning

confidence: 99%

In search of natural quasicrystals

Steinhardt

Bindi

2012

Rep. Prog. Phys.

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The concept of quasicrystals was first introduced twenty-eight years ago and, since then, over a hundred types have been discovered in the laboratory under precisely controlled physical conditions designed to avoid crystallization. Yet the original theory suggested that quasicrystals can potentially be as robust and stable as crystals, perhaps even forming naturally. These considerations motivated a decade-long search for a natural quasicrystal culminating in the discovery of icosahedrite (Al 63 Cu 24 Fe 13 ), an icosahedral quasicrystal found in a rock sample composed mainly of khatyrkite (crystalline (Cu,Zn)Al 2 ) labeled as coming from the Koryak Mountains of far eastern Russia. In this paper, we review the search and discovery, the analysis showing the sample to be of extraterrestrial origin and the initial results of an extraordinary geological expedition to the Koryak Mountains to seek further evidence.

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Distortion and Peak Broadening in Quasicrystal Diffraction Patterns

Cited by 256 publications

References 13 publications

Shock synthesis of quasicrystals with implications for their origin in asteroid collisions

Shock synthesis of quasicrystals with implications for their origin in asteroid collisions

The quest for forbidden crystals

In search of natural quasicrystals

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