Control and understanding of ensembles of skyrmions is important for realization of future technologies. In particular, the order-disorder transition associated with the 2D lattice of magnetic skyrmions can have significant implications for transport and other dynamic functionalities. To date, skyrmion ensembles have been primarily studied in bulk crystals, or as isolated skyrmions in thin film devices. Here, we investigate the condensation of the skyrmion phase at room temperature and zero field in a polar, van der Waals magnet. We demonstrate that we can engineer an ordered skyrmion crystal through structural confinement on the μm scale, showing control over this order-disorder transition on scales relevant for device applications.
We
have demonstrated a well-ordered In-rich single crystalline
InGaN nanoridge array grown on GaN/sapphire substrate using the integration
of top-down etching and bottom-up molecular beam epitaxy. During the
initial growth of InGaN on a patterned GaN/sapphire substrate, a (101̅1)
r-plane predominantly forms, suppressing the growth in [101̅1]
crystal direction and resulting in a triangular InGaN nanoprism. As
the growth proceeds further, a narrow (∼50 nm) single-crystal
fin-shaped InGaN nanoridge forms atop the InGaN nanoprism structure.
The resulting narrow fin-shaped InGaN nanoridge structure shows extremely
strong photoluminescence (PL) intensity with a center wavelength at
524–560 nm and narrow distribution compared to the epitaxially
grown planar InGaN layer or InGaN nanowire. High-resolution scanning
transmission electron microscopy (STEM) combined with an energy-dispersive
X-ray (EDS) map reveals that a sharply faceted single-crystal InGaN
nanoridge (∼50 nm width) forms along the top of each InGaN
nanoprism and is composed of Ga, In, and N without phase segregation
or dislocation. The single-crystalline In-rich InGaN nanoridge will
pave the way to design a viable architecture for a broad range of
III-nitride devices.
This is an Accepted Manuscript for the Microscopy and Microanalysis 2020 Proceedings. This version may be subject to change during the production process.
This is an Accepted Manuscript for the Microscopy and Microanalysis 2020 Proceedings. This version may be subject to change during the production process.
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