相关论文: Extent of stacking disorder in diamond
Diamond is known as the hardest substance due to its ultra-strong tetrahedral sp3 carbon bonding framework. The only weak link is its cubic cleavage planes between (111) buckled honeycomb layers. Compressing graphite single crystals and…
Hexagonal diamond, often called lonsdaleite, is an exotic allotrope of carbon, predicted to be harder than cubic (conventional) diamond with a wider bandgap. Due to its pure sp$^3$ bonded lattice, it should be expected to host sub-bandgap…
The electronic structure and dielectric properties of the diamond, body centered cubic diamond (bc8), and hexagonal diamond (lonsdaleite) phases of carbon are computed using density functional theory and many-body perturbation theory with…
We introduce a computational approach to estimate the hardness and stiffness of diamond surfaces and nanoparticles by studying their elastic response to atomic nanoindentation. Results of our ab initio density functional calculations…
The achievement of selectivity in the formation of cubic diamond is challenging due to the emergence of competing phases such as its hexagonal polymorph or clathrates possessing similar free energy. Although both polymorphs exhibit a…
Carbon at extreme conditions is the focus of intensive scientific inquiry due to its importance for applications in inertial confinement fusion experiments and for understanding the interior structure of carbon-rich exoplanets. The extreme…
Reports published in the last 25 years on the synthesis of carbon-based materials significantly superior to diamond in hardness and elastic properties have been critically examined, and three groups of recently appearing myths have been…
We explore the structural evolution of highly oriented pyrolytic graphite (HOPG) under detonation-induced shock conditions using in-situ synchrotron X-ray diffraction in the ns time scale. We observe the formation of hexagonal diamond…
Over the last few years, group IV hexagonal-diamond type crystals have acquired great attention in semiconductor physics thanks to the appearance of novel and very effective growth methods. However, many questions remain unaddressed on…
For materials science, diamond crystals are almost unrivaled for hardness and a range of other properties. Yet, when simply abstracting the carbon bonding structure as a geometric bar-and-joint periodic framework, it is far from rigid. We…
Surfaces of natural diamonds etched in high-pressure experiments in H2O, CO2 and H2O-NaCl fluids were investigated using Atomic Force Microscopy. Partial dissolution of the crystals produced several types of surface features including the…
New multi-core imaging fibre bundles -- hexabundles -- being developed at the University of Sydney will provide simultaneous integral field spectroscopy for hundreds of celestial sources across a wide angular field. These are a natural…
The assembly of colloidal cubic diamond is a challenging process since the shape and interaction parameters and the thermodynamic conditions where this structure is stable are elusive. The simultaneous use of shape-anisotropic particles and…
The motion of line defects (dislocations) has been studied for over 60 years but the maximum speed at which they can move is unresolved. Recent models and atomistic simulations predict the existence of a limiting velocity of dislocation…
Hexagonal SiGe is a promising material for combining electronic and photonic technologies. In this work, the energetic, structural, elastic and electronic properties of the hexagonal polytypes (2$H$, 4$H$ and 6$H$) of silicon and germanium…
Crystals are a state of matter characterised by periodic order. Yet crystalline materials can harbour disorder in many guises, such as non-repeating variations in composition, atom displacements, bonding arrangements, molecular…
Honeycomb layered oxides have garnered tremendous research interest in a wide swath of disciplines owing not only to the myriad physicochemical properties they exhibit, but also their rich crystal structural versatility. Herein, a…
Crystalline semiconductors may exist in different polytypic phases with significantly different electronic and optical properties. In this paper, we calculate the electronic structure and optical properties of diamond, Si and Ge in the…
To understand the crystal structure of n-diamond, a hydrogen-doped (H-doped) diamond model has been investigated using first principles calculations. In particular, hydrogen concentration dependent elastic constants and lattice parameters…
Recently synthesized hexagonal-diamond silicon, germanium, and silicon-germanium nanowires exhibit remarkable optical and electronic properties when compared to cubic-diamond polytypes. Because of the metastability of the hexagonal-diamond…