WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

Browse

Filters

2017 - 201912020 - 20221

Settings

Institution Author: search.filters.institutionAuthor.Sevinçli, HaldunPublisher: search.filters.publisher.American Chemical Society

Search Results

Now showing 1 - 2 of 2
  • Article
    Citation - WoS: 8
    Citation - Scopus: 9
    Toward Optimized Charge Transport in Multilayer Reduced Graphene Oxides
    (American Chemical Society, 2022) Çınar, Mustafa Neşet; Antidormi, Aleandro; Nguyen, Viet-Hung; Kovtun, Alessandro; Lara-Avila, Samuel; Liscio, Andrea; Charlier, Jean-Christophe; Roche, Stephan; Sevinçli, Haldun
    In the context of graphene-based composite applications, a complete understanding of charge conduction in multilayer reduced graphene oxides (rGO) is highly desirable. However, these rGO compounds are characterized by multiple and different sources of disorder depending on the chemical method used for their synthesis. Most importantly, the precise role of interlayer interaction in promoting or jeopardizing electronic flow remains unclear. Here, thanks to the development of a multiscale computational approach combining first-principles calculations with large-scale transport simulations, the transport scaling laws in multilayer rGO are unraveled, explaining why diffusion worsens with increasing film thickness. In contrast, contacted films are found to exhibit an opposite trend when the mean free path becomes shorter than the channel length, since conduction becomes predominantly driven by interlayer hopping. These predictions are favorably compared with experimental data and open a road toward the optimization of graphene-based composites with improved electrical conduction.
  • Article
    Citation - WoS: 41
    Citation - Scopus: 42
    Quartic Dispersion, Strong Singularity, Magnetic Instability, and Unique Thermoelectric Properties in Two-Dimensional Hexagonal Lattices of Group-Va Elements
    (American Chemical Society, 2017) Sevinçli, Haldun
    The critical points and the corresponding singularities in the density of states of crystals were first classified by Van Hove with respect to their dimensionality and energy-momentum dispersions. Here, different from saddle-point Van Hove singularities, the occurrence of a continuum of critical points, which give rise to strong singularities in two-dimensional elemental hexagonal lattices, is shown using a minimal tight-binding formalism. The model predicts quartic energy-momentum dispersions despite quadratic or linear ones, which is also the origin of the strong singularity. Starting with this model and using first-principles density functional theory calculations, a family of novel two-dimensional materials that actually display such singularities are identified and their extraordinary features are investigated. The strong singularity gives rise to ferromagnetic instability with an inverse-square-root temperature dependence and the quartic dispersion is responsible for a steplike transmission spectrum, which is a characteristic feature of one-dimensional systems. Because of the abrupt change in transmission at the band edge, these materials have temperature-independent thermopower and enhanced thermoelectric efficiencies. Nitrogene has exceptionally high thermoelectric efficiencies at temperatures down to 50 K, which could make low-temperature thermoelectric applications possible.