Publications by authors named "Luis Artus"
Tuning the Direct and Indirect Excitonic Transitions of -BN by Hydrostatic Pressure.
J Phys Chem C Nanomater Interfaces
June 2021
The pressure dependence of the direct and indirect bandgap transitions of hexagonal boron nitride is investigated using optical reflectance under hydrostatic pressure in an anvil cell with sapphire windows up to 2.5 GPa. Features in the reflectance spectra associated with the absorption at the direct and indirect bandgap transitions are found to downshift with increasing pressure, with pressure coefficients of -26 ± 2 and -36 ± 2 meV GPa, respectively.
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- Natural hyperbolic materials can confine long-wavelength electromagnetic waves, creating a phenomenon called hyperbolic phonon polaritons (HPPs) that operate below the diffraction limit.
- Research focuses on the behavior of HPPs in isotopically pure hexagonal boron nitride (hBN) and α-MoO crystals at cryogenic temperatures, revealing notably reduced energy losses.
- Findings indicate that HPPs in isotopic hBN have improved propagation lengths over 8 μm and lifetimes exceeding 5 ps, highlighting the potential for advancements in mid-infrared technologies at low temperatures.
The phonon linewidth of isotopically controlled hexagonal boron nitride (h-BN) single crystals has been determined by Raman scattering. The scattering by isotopic mass disorder induces a phonon broadening that is largest for boron 11 fractions around 0.65.
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