Publications by authors named "J Kalikka"

Oxide glasses are an elementary group of materials in modern society, but brittleness limits their wider usability at room temperature. As an exception to the rule, amorphous aluminum oxide (a-Al O ) is a rare diatomic glassy material exhibiting significant nanoscale plasticity at room temperature. Here, it is shown experimentally that the room temperature plasticity of a-Al O extends to the microscale and high strain rates using in situ micropillar compression.

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Molecular dynamics simulations using a density functional description of energies and forces have been carried out for a model of an as-deposited (AD) surface of amorphous selenium. The deposition model assumed the annealing (at 400 K) of layers of randomly located single atoms, followed by compression to the density used in earlier melt-quenched (MQ) simulations of amorphous Se, and by further annealing. The AD and MQ structures are predominantly twofold coordinated and similar, for example in the pair distribution functions, with notable differences: the AD structures have more defects (atoms with one and three neighbours), and the ring distributions differ.

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Article Synopsis
  • * Research reveals that amorphous aluminum oxide can deform without breaking at room temperature through a process called viscous creep, showing significant ductility.
  • * This finding suggests the potential to create more durable glass materials, enhancing the performance and reliability of electronics and batteries.
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We use an evolutionary algorithm to explore the design space of hexagonal GeSbTe; a van der Waals layered two dimensional crystal heterostructure. The GeSbTe structure is more complicated than previously thought. Predominant features include layers of GeSbTe and GeSbTe two dimensional crystals that interact through Te-Te van der Waals bonds.

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Strain engineering is an emerging route for tuning the bandgap, carrier mobility, chemical reactivity and diffusivity of materials. Here we show how strain can be used to control atomic diffusion in van der Waals heterostructures of two-dimensional (2D) crystals. We use strain to increase the diffusivity of Ge and Te atoms that are confined to 5 Å thick 2D planes within an Sb2Te3-GeTe van der Waals superlattice.

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