The effect of doping on the hardness of silicon carbide single crystal and its first principles calculations

When processing single crystal X-ray diffraction datasets for twins of Al2Cu sample synthesized by the high-pressure sintering (HPS) method, we have clarified why the crystal structure of Al2Cu was incorrectly solved about a century ago. The structural relationships between all existing Al2Cu phases, including the Owen-, θ-, θ’-, and Ω-Al2Cu phases, were investigated and established based on a proposed pseudo Al2Cu phase. Two potential phases have been built up by adjusting the packing sequences of A/B layers of Al atoms that were inherent in all existing Al2Cu phases. The mechanical, thermal, and dynamical stability of two such novel phases and their electronic properties were investigated by first-principles calculations.

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Reveal the fast and charge-insensitive lattice diffusion of silver in cubic silicon carbide via first-principles calculations

Computational Materials Science ◽

10.1016/j.commatsci.2019.109190 ◽

2019 ◽

Vol 170 ◽

pp. 109190 ◽

Cited By ~ 3

Author(s):

Qing Peng ◽

Nanjun Chen ◽

Zhijie Jiao ◽

Isabella J. van Rooyen ◽

William F. Skerjanc ◽

...

Keyword(s):

Silicon Carbide ◽

First Principles ◽

Lattice Diffusion ◽

First Principles Calculations ◽

Cubic Silicon Carbide

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Cycloaddition reactions on epitaxial graphene

New Journal of Chemistry ◽

10.1039/c9nj02528f ◽

2019 ◽

Vol 43 (28) ◽

pp. 11251-11257 ◽

Cited By ~ 1

Author(s):

Pablo A. Denis ◽

C. Pereyra Huelmo ◽

Federico Iribarne

Keyword(s):

Silicon Carbide ◽

Buffer Layer ◽

First Principles ◽

Epitaxial Graphene ◽

Cycloaddition Reactions ◽

First Principles Calculations

By means of first principles calculations we studied the occurrence of cycloaddition reactions on the buffer layer of silicon carbide. Interestingly, the presence of the substrate favors the 1,3 cycloaddition instead of the [2+2] or [4+2] ones.

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Structural analysis of Gd6FeBi2 from single-crystal X-ray diffraction methods and electronic structure calculations

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229619004868 ◽

2019 ◽

Vol 75 (5) ◽

pp. 562-567 ◽

Cited By ~ 4

Author(s):

Jiliang Zhang ◽

Yong-Mook Kang ◽

Guangcun Shan ◽

Svilen Bobev

Keyword(s):

Electronic Structure ◽

Single Crystal ◽

First Principles ◽

Earth Metal ◽

Magnetic Ordering ◽

Additional Contribution ◽

First Principles Calculations ◽

X Ray Diffraction ◽

Magnetic Exchange ◽

X Ray

The crystal structure of the gadolinium iron bismuthide Gd6FeBi2 has been characterized by single-crystal X-ray diffraction data and analyzed in detail using first-principles calculations. The structure is isotypic with the Zr6CoAl2 structure, which is a variant of the ZrNiAl structure and its binary prototype Fe2P (Pearson code hP9, Wyckoff sequence g f d a). As such, the structure is best viewed as an array of tricapped trigonal prisms of Gd atoms centered alternately by Fe and Bi. The magnetic-ordering temperature of this compound (ca 350 K) is much higher than that of other rare-earth metal-rich phases with the same or related structures. It is also higher than the ordering temperature of many other Gd-rich ternary phases, where the magnetic exchange is typically governed by Ruderman–Kittel–Kasuya–Yosida (RKKY) interactions. First-principles calculations reveal a larger than expected Gd magnetic moment, with the additional contribution arising from the Gd 5d electrons. The electronic structure analysis suggests strong Gd 5d–Fe 3d hybridization to be the cause of this effect, rather than weak interactions between Gd and Bi. These details are of importance for understanding the magnetic response and explaining the high ordering temperature in this material.

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The influence of palladium impurities on vacancy diffusion in cubic silicon carbide

MRS Proceedings ◽

10.1557/proc-1264-bb06-03 ◽

2010 ◽

Vol 1264 ◽

Author(s):

Guido Roma

Keyword(s):

Silicon Carbide ◽

First Principles ◽

Kinetic Properties ◽

Vacancy Diffusion ◽

First Principles Calculations ◽

Low Concentrations ◽

Diffusion Mechanisms ◽

Cubic Silicon Carbide ◽

As Solubility ◽

Correlation Factors

AbstractThe basic properties of palladium impurities in silicon carbide, such as solubility or diffusion mechanisms, are far from being well understood. In a recent paper I presented a systematic study of stability and kinetic properties of Pd in cubic silicon carbide using first principles calculations. In this paper I focus on the effect of the presence of palladium in silicon carbide, even in very low concentrations, on the kinetic properties of carbon vacancies. I apply a odel of Pd diffusion through a vacancy mechanism on the carbon sublattice and extract the correlation factors leading to an enhancement of vacancy migration, due to the coupling of iffusion fluxes between vacancies and palladium impurities.

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