Yazar "Gorkan, Taylan" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Above Room Temperature Ferromagnetism in Gd2B2 Monolayer with High Magnetic Anisotropy
    (Amer Chemical Soc, 2020) Gorkan, Taylan; Vatansever, Erol; Akinci, Umit; Gokoglu, Gokhan; Akturk, Ethem; Ciraci, Salim
    The realization of 2D ultrathin crystals with a ferromagnetic ground state that is sustainable at room temperature has been a real challenge now. By combining ab initio density functional theory with Monte Carlo simulations, we predicted a new 2D structure, Gd2B2 monolayer, which maintains its mechanical stability at elevated temperatures. More remarkably, it has a ferromagnetic ground state with high permanent magnetic moment, which persists far above room temperature. It exhibits high magnetocrystalline anisotropy along particular directions. We find also that both its magnetic anisotropy and Curie temperature can largely be altered by applied strain providing an excellent magnetoelastic tunability. This novel 2D crystal with high magnetic moment and Curie temperature combined with high structural and thermal stability can offer critical applications in magnetoelectronics.
  • Küçük Resim Yok
    Öğe
    Electronic structure, cohesive and magnetic properties of iridium oxide clusters adsorbed on graphene
    (Elsevier Science Inc, 2020) Aysan, Isil Ilgaz; Gorkan, Taylan; Ozdemir, Ilkay; Kadioglu, Yelda; Gokoglu, Gokhan; Akturk, Ethem
    In this study, we investigated and revealed the electronic properties, geometric structures and binding behavior of small (IrO)(n) and (IrO2)(n) (n = 1-5) clusters within first principles calculations based on the density functional theory. The electronic and magnetic properties of small nanoclusters displayed significant size dependency due to strong quantum confinement effect. Moreover we considered the binding and structural modification of the clusters on graphene surface as a substrate. The cohesive energy per atom of isolated clusters increased with size of the cluster n. This shows that the increase in coordination number results in a more stable nanocluster with increased number of saturated bonds. Pristine (IrO)(n) and (IrO2)(n) clusters presented different structural motives at equilibrium. The ground states of (IrO) n and (IrO2)(n) clusters considered in this study were all magnetic except for (IrO)(4), (IrO2)(2), and (IrO2)(4). HOMO-LUMO gap E-HLG values displayed large variations due to size of the cluster, hence bond saturation. The structural configurations of free standing nanoclusters are slightly modified, when adsorbed on graphene. The adsorption behavior of a cluster on graphene was improved by an applied electric field yielding larger binding energy and larger charger transfer. We observed that electronic and magnetic ground state of the clusters strongly depend on optimized structural configuration for both bare and adsorbed on graphene monolayer. (C) 2020 Elsevier Inc. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Novel Metallic Clathrates of Group-IV Elements and Their Compounds in a Dense Hexagonal Lattice
    (Amer Chemical Soc, 2019) Gorkan, Taylan; Ozdemir, Ilkay; Bakir, M. Yagiz; Ersan, Fatih; Gokoglu, Gokhan; Akturk, Ethem; Ciraci, Salim
    Further, to recently introduced metallic NaSi6 and Si-6 clathrate structures, we show that not only Si but also other group-IV elements, such as C, Ge, and Sn, can form stable and metallic clathrate structures with open channels at the corners of hexagons. These elemental clathrates of Si, Ge, and Sn can be viewed as if they are a combination of 2D metallic planes and perpendicular 1D metallic chains, the interplay of which can give rise to interesting physical effects. 'When free-standing, these atomic planes transform to 2D semiconducting, single-layer structures. The clathrate structure of C, which consists of weakly interacting, vertical hexagonal tubes situated at the corners of a 2D hexagonal lattice, is insulating in the plane but 1D metallic perpendicular to the planes. We also show that stable compound clathrate structures can form by hosting different alkali, alkaline earth, and light transition metal atoms in the open channels of elemental clathrates. These new metallic allotropes of group-IV elements predicted by first-principles calculations based on the density functional theory exhibit features that can be critical fundamentally and technologically.