The Experts below are selected from a list of 8823 Experts worldwide ranked by ideXlab platform

D. I. Palade - One of the best experts on this subject based on the ideXlab platform.

  • Multiple surface plasmons on an unbounded quantum plasma half-space
    arXiv: Plasma Physics, 2016
    Co-Authors: D. I. Palade
    Abstract:

    The propagation of surface plasmons on a quantum plasma half-space in the absence of any external confinement is investigated. By means of Quantum Hydrodynamic Model in the electrostatic limit it is found that the Equilibrium Density Profile is a smooth continuous function which, in the linear regime, supports multiple non-normal surface modes. Defining a spectrum function and using a cutting condition, the dispersion relations of these modes and their relevance for realistic dynamics are computed. It is found that the multiple surface plasmons present a significant red-shift with respect to the case of fully bounded quantum plasmas.

  • Multiple surface plasmons in an unbounded quantum plasma half-space
    Physics of Plasmas, 2016
    Co-Authors: D. I. Palade
    Abstract:

    The propagation of surface plasmons on a quantum plasma half-space in the absence of any external confinement is investigated. By means of the Quantum Hydrodynamic Model in the electrostatic limit, it is found that the Equilibrium Density Profile is a smooth continuous function which, in the linear regime, supports multiple non-normal surface modes. Defining a spectrum function and using a cutting condition, the dispersion relations of these modes and their relevance for realistic dynamics are computed. It is found that the multiple surface plasmons present a significant red-shift with respect to the case of fully bounded quantum plasmas.

John G. Curro - One of the best experts on this subject based on the ideXlab platform.

  • Van der Waals model for phase transitions in thermoresponsive surface films
    The Journal of chemical physics, 2009
    Co-Authors: John D. Mccoy, John G. Curro
    Abstract:

    Phase transitions in polymeric surface films are studied with a simple model based on the van der Waals equation of state. Each chain is modeled by a single bead attached to the surface by an entropic-Hooke’s law spring. The surface coverage is controlled by adjusting the chemical potential, and the Equilibrium Density Profile is calculated with Density functional theory. The interesting feature of this model is the multivalued nature of the Density Profile seen at low temperature. This van der Waals loop behavior is resolved with a Maxwell construction between a high-Density phase near the wall and a low-Density phase in a “vertical” phase transition. Signatures of the phase transition in experimentally measurable quantities are then found. Numerical calculations are presented for isotherms of surface pressure, for the Poisson ratio, and for the swelling ratio.

V. V. Popov - One of the best experts on this subject based on the ideXlab platform.

  • terahertz plasmon photoresponse in a Density modulated two dimensional electron channel of a gaas algaas field effect transistor
    Applied Physics Letters, 2007
    Co-Authors: G. Aizin, D V Fateev, G. M. Tsymbalov, V. V. Popov
    Abstract:

    We present a theory of dc photoresponse, change in device conductance, at the plasmon resonance in the Density modulated two-dimensional electron channel of the grating-gated GaAs∕AlGaAs field-effect transistor irradiated by an electromagnetic wave of terahertz frequency. An Equilibrium Density modulation is shown to give rise to a specific mechanism of photoresponse due to a plasma electrostriction effect. In strongly modulated systems, this effect dominates the photoresponse and results in a strong increase of the resonant peak amplitudes and photoresponse sign reversal dependent on the modulation depth and the Equilibrium Density Profile. These results are in good qualitative agreement with recent experiments.

  • Terahertz plasmon photoresponse in a Density modulated two-dimensional electron channel of a GaAs/AlGaAs field-effect transistor
    Applied Physics Letters, 2007
    Co-Authors: G. Aizin, D V Fateev, G. M. Tsymbalov, V. V. Popov
    Abstract:

    We present a theory of dc photoresponse, change in device conductance, at the plasmon resonance in the Density modulated two-dimensional electron channel of the grating-gated GaAs∕AlGaAs field-effect transistor irradiated by an electromagnetic wave of terahertz frequency. An Equilibrium Density modulation is shown to give rise to a specific mechanism of photoresponse due to a plasma electrostriction effect. In strongly modulated systems, this effect dominates the photoresponse and results in a strong increase of the resonant peak amplitudes and photoresponse sign reversal dependent on the modulation depth and the Equilibrium Density Profile. These results are in good qualitative agreement with recent experiments.

John D. Mccoy - One of the best experts on this subject based on the ideXlab platform.

  • Van der Waals model for phase transitions in thermoresponsive surface films
    The Journal of chemical physics, 2009
    Co-Authors: John D. Mccoy, John G. Curro
    Abstract:

    Phase transitions in polymeric surface films are studied with a simple model based on the van der Waals equation of state. Each chain is modeled by a single bead attached to the surface by an entropic-Hooke’s law spring. The surface coverage is controlled by adjusting the chemical potential, and the Equilibrium Density Profile is calculated with Density functional theory. The interesting feature of this model is the multivalued nature of the Density Profile seen at low temperature. This van der Waals loop behavior is resolved with a Maxwell construction between a high-Density phase near the wall and a low-Density phase in a “vertical” phase transition. Signatures of the phase transition in experimentally measurable quantities are then found. Numerical calculations are presented for isotherms of surface pressure, for the Poisson ratio, and for the swelling ratio.

Thorsten Hiester - One of the best experts on this subject based on the ideXlab platform.

  • From Density to interface fluctuations: the origin of wavelength dependence in surface tension.
    Physical Review E, 2008
    Co-Authors: Thorsten Hiester
    Abstract:

    The height-height correlation function for a fluctuating interface between two coexisting bulk phases is derived by means of general Equilibrium properties of the corresponding Density-Density correlation function. A wavelength-dependent surface tension gamma(q) can be defined and expressed in terms of the direct correlation function c(r,r;{'}) , the Equilibrium Density Profile rho_{0}(r) , and an operator which relates Density to surface configurations. Neither the concept of an effective interface Hamiltonian nor the difference in pressure is needed to determine the general structure of the height-height correlations or gamma(q) , respectively. This result generalizes the Mecke-Dietrich surface tension gamma_{MD}(q) [Phys. Rev. E 59, 6766 (1999)] and modifies recently published criticism concerning gamma_{MD}(q) [Tarazona, Checa, and Chacon, Phys. Rev. Lett. 99, 196101 (2007)].