Controlled formation of metastable germanium polymorphs

Haberl, Bianca; Guthrie, Malcolm; Malone, Brad D.; Smith, Jesse S.; Sinogeikin, Stanislav V.; Cohen, Marvin L.; Williams, James S.; Shen, Guoyin; Bradby, Jodie

doi:10.1103/physrevb.89.144111

Cited by 48 publications

(55 citation statements)

References 44 publications

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“…Phase transformation pathways are strongly influenced by the time dependence of the driving mechanism (compression, thermal transfer, strain, irradiation, etc.). This rapid compression and decompression capability allows studies of the nucleation of phase transitions, phase growth, and metastable phases at various compression rates [104,106,110,111]. In particular, this capability covers the region of compression rates between static techniques (DACs and LVPs) and dynamic shock-driven devices (gas guns, explosive, magnetic pulse compression, and laser shock), a region that has been sparsely explored.…”

Section: Rapid Compression and Decompressionmentioning

confidence: 99%

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High-pressure studies with x-rays using diamond anvil cells

2016

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Pressure profoundly alters all states of matter. The symbiotic development of ultrahighpressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials' properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and magnetic properties of materials over a wide range of pressure-temperature conditions.

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Section: Rapid Compression and Decompressionmentioning

confidence: 99%

“…When screws are rapidly turned, pressures may be changed quickly; for example, synthesizing metastable phases of Si and Ge when quickly decompressed from HP phases [103,104]. Recently, the dynamic DAC (dDAC) has been developed for repetitively applying time-dependent load-to-pressure cycles [105][106][107].…”

Section: Rapid Compression and Decompressionmentioning

confidence: 99%

High-pressure studies with x-rays using diamond anvil cells

2016

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“…It should be noted that 1 of 20 indents with a residual load of 0 mN and loading/unloading rate of 50 mN/s has peaks around 195, 250, and 280 cm −1 corresponding to st12-Ge. The phase transformation caused by shear does not contain r8-Ge [7,14,17], so friction during LHT might prevent the formation of r8-Ge under ∆P = 0 mN compared with ∆P = 2 mN even though the phase transformation to r8-Ge was still dominant compared to other higher ∆P. However, there may well be other explanations for the lower r8-Ge probability for the 0 mN LHT case, and further experiments would be needed to resolve this issue.…”

Section: Effects Of Indentation Modes On Phase Transformation Behaviorsmentioning

confidence: 99%

“…The case for ∆P = 0 mN means that the load was completely removed from the sample, and the indenter tip might leave the sample surface. In such a case, friction might occur at the second contact and cause shear in the Ge sample, which could lead to phase transformation to dc-Ge or st12-Ge [7,14,17]. It should be noted that 1 of 20 indents with a residual load of 0 mN and loading/unloading rate of 50 mN/s has peaks around 195, 250, and 280 cm −1 corresponding to st12-Ge.…”

Section: Effects Of Indentation Modes On Phase Transformation Behaviorsmentioning

confidence: 99%

“…Previous studies reported that diamond cubic Ge (dc-Ge) transforms to metallic (β-Sn)-Ge at a pressure of~10 GPa [1][2][3][4]. When the pressure releases, this metallic phase transforms to various metastable structures depending on the experimental conditions, such as simple tetragonal phase (st12-Ge) [5][6][7][8], rhombohedral phase (r8-Ge) [6,7,9,10], body centered cubic phase (bc8-Ge) [5,6,11], as well as amorphous Ge (a-Ge) and dc-Ge as end phases [8,11]. Another phase of hexagonal diamond Ge (hd-Ge) is also confirmed by compression of a-Ge [9,12,13].…”

Section: Introductionmentioning

confidence: 99%

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Comparative Study of Phase Transformation in Single-Crystal Germanium during Single and Cyclic Nanoindentation

Kosai¹,

Huang²,

Yan³

2017

Crystals

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Single-crystal germanium is a semiconductor material which shows complicated phase transformation under high pressure. In this study, new insight into the phase transformation of diamond-cubic germanium (dc-Ge) was attempted by controlled cyclic nanoindentation combined with Raman spectroscopic analysis. Phase transformation from dc-Ge to rhombohedral phase (r8-Ge) was experimentally confirmed for both single and cyclic nanoindentation under high loading/unloading rates. However, compared to single indentation, double cyclic indentation with a low holding load between the cycles caused more frequent phase transformation events. Double cyclic indentation caused more stress in Ge than single indentation and increased the possibility of phase transformation. With increase in the holding load, the number of phase transformation events decreased and finally became less than that under single indentation. This phenomenon was possibly caused by defect nucleation and shear accumulation during the holding process, which were promoted by a high holding load. The defect nucleation suppressed the phase transformation from dc-Ge to r8-Ge, and shear accumulation led to another phase transformation pathway, respectively. A high holding load promoted these two phenomena, and thus decreased the possibility of phase transformation from dc-Ge to r8-Ge.

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Hexagonal Si−Ge Class of Semiconducting Alloys Prepared by Using Pressure and Temperature

Serghiou

Odling

Reichmann

et al. 2021

Chemistry A European J

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Multi-anvil and laser-heated diamond anvil methods have been used to subject Ge and Si mixtures to pressures and temperatures of between 12 and 17 GPa and 1500-1800 K, respectively. Synchrotron angle dispersive X-ray diffraction, precession electron diffraction and chemical analysis using electron microscopy, reveal recovery at ambient pressure of hexagonal GeÀ Si solid solutions (P6 3 / mmc). Taken together, the multi-anvil and diamond anvil results reveal that hexagonal solid solutions can be prepared for all GeÀ Si compositions. This hexagonal class of solid solutions constitutes a significant expansion of the bulk GeÀ Si solid solution family, and is of interest for optoelectronic applications.

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Controlled formation of metastable germanium polymorphs

Cited by 48 publications

References 44 publications

High-pressure studies with x-rays using diamond anvil cells

High-pressure studies with x-rays using diamond anvil cells

Comparative Study of Phase Transformation in Single-Crystal Germanium during Single and Cyclic Nanoindentation

Hexagonal Si−Ge Class of Semiconducting Alloys Prepared by Using Pressure and Temperature

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