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F M Peeters - One of the best experts on this subject based on the ideXlab platform.

  • effect of a perpendicular magnetic field on the shallow donor states near a semiconductor Metal Interface
    Physical Review B, 2013
    Co-Authors: A P Djotyan, Y L Hao, A A Avetisyan, F M Peeters
    Abstract:

    We investigate the influence of an external perpendicular magnetic field on the lowest-energy states of an electron bound to a donor which is located near a semiconductor-Metal Interface. The problem is treated within the effective mass approach and the lowest-energy states are obtained through (1) the “numerically exact” finite element method, and (2) a variational approach using a trial wave function where all image charges that emerge due to the presence of the Metallic gate are taken into account. The trial wave functions are constructed such that they reduce to an exponential behavior for sufficiently small magnetic fields and become Gaussian for intermediate and large magnetic fields. The average electron-donor distance can be controlled by the external magnetic field. We find that the size of the 2pz state depends strongly on the magnetic field when the donor is close to the Interface, showing a nonmonotonic behavior, in contrast with the ground and the other excited states.

  • shallow donor states near a semiconductor insulator Metal Interface
    Physical Review B, 2009
    Co-Authors: Y L Hao, A P Djotyan, A A Avetisyan, F M Peeters
    Abstract:

    Y. L. Hao,1 A. P. Djotyan,2 A. A. Avetisyan,1,2 and F. M. Peeters1,3,* 1Department of Physics, University of Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium 2Department of Physics, Yerevan State University, A. Manoogian 1, Yerevan 0025, Armenia 3Departamento de Fisica, Universidade Federal do Ceara, Caixa Postal 6030, Campus do Pici, Fortaleza 60455-900, CE, Brazil Received 7 April 2009; revised manuscript received 8 July 2009; published 30 July 2009

Duncan J Mowbray - One of the best experts on this subject based on the ideXlab platform.

  • understanding energy level alignment in donor acceptor Metal Interfaces from core level shifts
    ACS Nano, 2013
    Co-Authors: A Elsayed, Patrizia Borghetti, E Goiri, Celia Rogero, Luca Floreano, Giacomo Lovat, Duncan J Mowbray
    Abstract:

    The molecule/Metal Interface is the key element in charge injection devices. It can be generally defined by a monolayer-thick blend of donor and/or acceptor molecules in contact with a Metal surface. Energy barriers for electron and hole injection are determined by the offset from HOMO (highest occupied) and LUMO (lowest unoccupied) molecular levels of this contact layer with respect to the Fermi level of the Metal electrode. However, the HOMO and LUMO alignment is not easy to elucidate in complex multicomponent, molecule/Metal systems. We demonstrate that core-level photoemission from donor–acceptor/Metal Interfaces can be used to straightforwardly and transparently assess molecular-level alignment. Systematic experiments in a variety of systems show characteristic binding energy shifts in core levels as a function of molecular donor/acceptor ratio, irrespective of the molecule or the Metal. Such shifts reveal how the level alignment at the molecule/Metal Interface varies as a function of the donor–accep...

Yoshichika Otani - One of the best experts on this subject based on the ideXlab platform.

  • detection of the interfacial exchange field at a ferromagnetic insulator nonmagnetic Metal Interface with pure spin currents
    Physical Review B, 2018
    Co-Authors: P K Muduli, Motoi Kimata, Yasutomo Omori, T Wakamura, Saroj P Dash, Yoshichika Otani
    Abstract:

    At the Interface between a nonmagnetic Metal (NM) and a ferromagnetic insulator (FI) spin current can interact with the magnetization, leading to a modulation of the spin current. The interfacial exchange field at these FI-NM Interfaces can be probed by placing the Interface in contact with the spin transport channel of a lateral spin valve (LSV) device and observing additional spin relaxation processes. We study interfacial exchange field in lateral spin valve devices where a Cu spin transport channel is in proximity with ferromagnetic insulator EuS (EuS-LSV) and yttrium iron garnet Y3Fe5O12 (YIG-LSV). The spin signals were compared with reference lateral spin valve devices fabricated on nonmagnetic Si/SiO2 substrate with MgO or AlOx capping. The nonlocal spin valve signal is about 4 and 6 times lower in the EuS-LSV and YIG-LSV, respectively. The suppression in the spin signal has been attributed to enhanced surface spin-flip probability at the Cu-EuS (or Cu-YIG) Interface due to an interfacial spin-orbit field. Besides spin signal suppression we also found a widely observed low temperature peak in the spin signal at T similar to 30 K is shifted to higher temperature in the case of devices in contact with EuS or YIG. Temperature dependence of the spin signal for different injector-detector distances reveal fluctuating exchange field at these Interfaces cause additional spin decoherence which limit spin relaxation time in addition to conventional sources of spin relaxation. Our results show that temperature-dependent measurement with pure spin current can be used to probe interfacial exchange field at the ferromagnetic insulator-nonmagnetic Metal Interface.

X R Wang - One of the best experts on this subject based on the ideXlab platform.

  • thermal spin current and spin accumulation at ferromagnetic insulator nonmagnetic Metal Interface
    Physical Review B, 2016
    Co-Authors: Yuhua Shen, Xiansi Wang, X R Wang
    Abstract:

    Spin current injection and spin accumulation near a ferromagnetic insulator (FI)/nonmagnetic Metal (NM) bilayer film under a thermal gradient is investigated theoretically. Using the Fermi golden rule and the Boltzmann equations, we find that FI and NM can exchange spins via interfacial electron-magnon scattering because of the imbalance between magnon emission and absorption caused by either non-equilibrium distribution of magnons or non-equilibrium between magnons and electrons. A temperature gradient in FI and/or a temperature difference across the FI/NM Interface generates a spin current which carries angular momenta parallel to the magnetization of FI from the hotter side to the colder one. Interestingly, the spin current induced by a temperature gradient in NM is negligibly small due to the nonmagnetic nature of the non-equilibrium electron distributions. The results agree well with all existing experiments.

A P Djotyan - One of the best experts on this subject based on the ideXlab platform.

  • effect of a perpendicular magnetic field on the shallow donor states near a semiconductor Metal Interface
    Physical Review B, 2013
    Co-Authors: A P Djotyan, Y L Hao, A A Avetisyan, F M Peeters
    Abstract:

    We investigate the influence of an external perpendicular magnetic field on the lowest-energy states of an electron bound to a donor which is located near a semiconductor-Metal Interface. The problem is treated within the effective mass approach and the lowest-energy states are obtained through (1) the “numerically exact” finite element method, and (2) a variational approach using a trial wave function where all image charges that emerge due to the presence of the Metallic gate are taken into account. The trial wave functions are constructed such that they reduce to an exponential behavior for sufficiently small magnetic fields and become Gaussian for intermediate and large magnetic fields. The average electron-donor distance can be controlled by the external magnetic field. We find that the size of the 2pz state depends strongly on the magnetic field when the donor is close to the Interface, showing a nonmonotonic behavior, in contrast with the ground and the other excited states.

  • shallow donor states near a semiconductor insulator Metal Interface
    Physical Review B, 2009
    Co-Authors: Y L Hao, A P Djotyan, A A Avetisyan, F M Peeters
    Abstract:

    Y. L. Hao,1 A. P. Djotyan,2 A. A. Avetisyan,1,2 and F. M. Peeters1,3,* 1Department of Physics, University of Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium 2Department of Physics, Yerevan State University, A. Manoogian 1, Yerevan 0025, Armenia 3Departamento de Fisica, Universidade Federal do Ceara, Caixa Postal 6030, Campus do Pici, Fortaleza 60455-900, CE, Brazil Received 7 April 2009; revised manuscript received 8 July 2009; published 30 July 2009