Publications by authors named "C G Van de Walle"
Article Synopsis
- * ScAlN is particularly intriguing for nanophotonic applications due to its large bandgap suitable for blue wavelengths and its potential for enhanced nonlinear optical characteristics.
- * The study examines ScAlN's Pockels effect, showing that while its electro-optic coupling is initially weak, it can be significantly improved with higher scandium doping, potentially outperforming lithium niobate in certain applications.
Article Synopsis
- Transition-metal centers, specifically chromium (Cr) and manganese (Mn), show potential as paramagnetic spin defects in wide-bandgap semiconductors like AlN and GaN, making them valuable for applications in nanophotonics and quantum information processing.
- The study employs advanced hybrid density functional theory to analyze the electronic structure, stability, and optical properties of these centers, predicting their behavior and interactions under various conditions.
- Results indicate that these substitutional centers produce narrow quantum emissions around 1.2 eV, confirming their potential as effective spin qubits due to their favorable zero-field splitting parameters and proposed optical spin polarization methods.*
Dimensionality effects on trap-assisted recombination: the Sommerfeld parameter.
J Phys Condens Matter
February 2024
Article Synopsis
- The Sommerfeld parameter measures how the presence of a charged center affects charge density in solids, particularly in the context of free carriers in condensed matter physics.
- This study derives the Sommerfeld parameter for one and two-dimensional systems and compares it with existing three-dimensional results.
- Findings show that lower dimensionality leads to a suppression of trap-assisted recombination, highlighting the importance of dimensionality in electronic properties.
Article Synopsis
- Trap-assisted nonradiative recombination (TAAM) significantly reduces optoelectronic device efficiency, especially in wide-band-gap materials where conventional models like multiphonon emission (MPE) don't fully explain the losses.
- This study introduces a new methodology to calculate TAAM rates caused by defects or impurities and evaluates its effects on light emitter efficiency, highlighting the importance of considering both TAAM and MPE in recombination cycles.
- Specifically examining the impact of a calcium impurity in InGaN, the findings indicate that for materials with band gaps over 2.5 eV, TAAM can drastically increase recombination rates, making it a key factor in nonradiative processes in wide-band-gap semiconductors.
Fibrillation is a challenge commonly encountered in the formulation and development of therapeutic peptides. Cucurbit[7]urils (CB[7]), a group of water soluble macrocycles, have been reported to suppress fibrillation in insulin and human calcitonin through association with Phe and Tyr residues which drive fibril formation. Here, we report the effect of CB[7] on the fibrillation behavior of the HIV fusion inhibitor enfuvirtide (ENF) that contains N-terminal Tyr and C-terminal Phe residues.
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