فهرس المقالات Quantum transport

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  1 - Abnormal electronic transport in disordered four-terminal graphene nanodevice
  Amirhossein Ahmadkhan Kordbacheh Azadeh Jafari Mehdi Afshar Arjmand
  10.1186/2251-7235-7-54
  AbstractIn this paper, a numerical study of quantum transport in a disordered four-terminal graphene nanodevice is investigated based on the Landauer approach. The effects of impurity on transmission coefficient of the electron injected into the system are studied using أکثر

  AbstractIn this paper, a numerical study of quantum transport in a disordered four-terminal graphene nanodevice is investigated based on the Landauer approach. The effects of impurity on transmission coefficient of the electron injected into the system are studied using tight-binding model. In this manner, we emphasize that when the disorder density is sufficiently large, the transmission coefficients and the current reduce due to multiscattering phenomenon. We have found that the perfectly conducting channel develops in four-terminal device in its zigzag edge if the range of impurity gets exponentially wider. The theoretical results obtained can be a base for the development in designing graphene nanodevice. تفاصيل المقالة
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  2 - Investigation of structural and electronic transport properties of graphene and graphane using maximally localized Wannier functions
  Mansoureh Pashangpour Vahid Ghaffari
  10.1186/2251-7235-7-9
  AbstractIn this work, we have investigated one-sided and two-sided fully saturated hydrocarbons with C:H formula derived from a single sheet of graphene, which are called table-like and chair-like graphanes. The effects of full hydrogenation of graphene sheet, graphane, أکثر

  AbstractIn this work, we have investigated one-sided and two-sided fully saturated hydrocarbons with C:H formula derived from a single sheet of graphene, which are called table-like and chair-like graphanes. The effects of full hydrogenation of graphene sheet, graphane, were studied using generalized gradient approximation of the density functional theory and the pseudopotential method. Total energy calculations show that chair-like conformer of graphane is more favorable than table-like one. A change of hybridization from sp2 to sp3 for chair-like conformer of graphane has been achieved. After full geometric relaxation of graphene and two phases of graphane, we obtain the adsorption geometry, adsorption energies, charge transfer, energy gap, density of states, quantum conductivity, and current for graphene and graphane. We show that the band gap induced by hydrogenation of graphene sheet in table-like conformer can greatly improve the electrical characteristics of graphene-based field effect transistors and its on/off ratio. We identify that graphene is acting as an acceptor after saturation with hydrogen. تفاصيل المقالة
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  3 - Electronic transport in Si and Au monoatomic chains considering strongly correlation effect, a first principle study
  Mansoureh Pashangpour Vahid Ghaffari
  We have investigated structure and electronic properties of Au and Si liner chains using the firstprinciplesplane wave pseudopotential method. The transport properties and conductance of these twoliner chains are studied using Landauer approaches based on density functi أکثر

  We have investigated structure and electronic properties of Au and Si liner chains using the firstprinciplesplane wave pseudopotential method. The transport properties and conductance of these twoliner chains are studied using Landauer approaches based on density functional theory (DFT). Weobtain density of states and band gap using Kohn-Sham and Wannier functions as well as quantumconductivity and current for Au and Si liner chains. We study the effect of Hubbard U on quantumconductivity and current for Au liner chain within DFT+U for strongly correlated systems. Wecompare the source of the states around Fermi level of these systems that have important role inconductivity. We present I-V characteristics of the Si and Au liner chain. Results show Ohmicbehavior of current flow in the liner chains in terms of applied bias voltage. We show that Hubbard Ucorrection removes the unphysical contribution of d electrons to the conductance of Au liner chain,resulting in a single transmission channel and a more realistic conductance of 1G0 that is in goodagreement with experimental results. Our calculations reveal that monatomic chains of Si and Au aremetallic therefore they can be used as connectors between nanoelectronic devices. تفاصيل المقالة