نتایج جستجو برای: magnetic impurity

تعداد نتایج: 346950  

Journal: :Physical review letters 2015
K Hirsch V Zamudio-Bayer A Langenberg M Niemeyer B Langbehn T Möller A Terasaki B V Issendorff J T Lau

The magnetic moment of a single impurity atom in a finite free electron gas is studied in a combined x-ray magnetic circular dichroism spectroscopy, charge transfer multiplet calculation, and density functional theory study of size-selected free chromium-doped gold clusters. The observed size dependence of the local magnetic moment can be understood as a transition from a local moment to a mixe...

Journal: :Physical review letters 2006
R Guerrero F G Aliev Y Tserkovnyak T S Santos J S Moodera

We report the experimental observation of sub-Poissonian shot noise in single magnetic tunnel junctions, indicating the importance of tunneling via impurity levels inside the tunnel barrier. For junctions with weak zero-bias anomaly in conductance, the Fano factor (normalized shot noise) depends on the magnetic configuration being enhanced for antiparallel alignment of the ferromagnetic electro...

Journal: :Microelectronics Journal 2008
Pablo Villamil Carlos Cabra N. Porras-Montenegro

In this work using the effective-mass approximation within a variational approach we study the effect of the 3D longitudinal optical phonons on the energy of a shallow donor impurity in a GaAs–(Ga,Al)As quantum-well wire with a magnetic field applied in the wireaxis direction. We obtain the energy of the lower impurity states as a function of the wire radius, the donor position inside the wire,...

2007
M. ICHIMURA

The electronic structure of diluted magnetic semiconductors is studied, especially focusing on the hole character. The Haldane-Anderson model is extend to a magnetic impurity, and is analyzed in the Hartree-Fock approximation. Due to the strong hybridization of an impurity d-states with host p-states, it is shown that holes are created in the valence band, at the same time the localized magneti...

2008
Hongchen Fu Allan I Solomon Xiaoguang Wang

For a 3-qubit Heisenberg model in a uniform magnetic field, the pairwise thermal entanglement of any two sites is identical due to the exchange symmetry of sites. In this paper we consider the effect of a non-uniform magnetic field on the Heisenberg model, modeling a magnetic impurity on one site. Since pairwise entanglement is calculated by tracing out one of the three sites, the entanglement ...

فربد, منصور, زرگرشوشتری, مرتضی , پورمقدم, امیر ,

In this article, the Zn1-xNixO nanoparticles with x= 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.08 and 0.1 have been produced by mechanochemical method. To investigate the structural, morphological, optical and magnetic properties of the samples, the X-ray diffraction, field emission scanning electron microscope, UV-visible spectroscopy, photoluminescence and vibrating sample magnetometer have been use...

2014
Shang-Chun Lu Jean-Pierre Leburton

We provide a systematic and theoretical study of the electronic properties of a large number of impurities, vacancies, and adatoms in monolayer MoS2, including groups III and IV dopants, as well as magnetic transition metal atoms such as Mn, Fe, Co, V, Nb, and Ta. By using density functional theory over a 5 × 5 atomic cell, we identify the most promising element candidates for p-doping of MoS2....

2010
P. W. Terry V. Tangri J. S. Sarff G. Fiksel A. F. Almagri Y. Ren S. C. Prager

In the reversed field pinch ions are heated anomalously relative to collisional energy exchange with Ohmically heated electrons. The process channels electron energy to ions in a way that is still not understood. Recent observations suggest that impurities are preferentially heated. A theory for ion heating via impurity ioncyclotron-resonant damping of the turbulent energy cascaded from unstabl...

Journal: :Physical review letters 2004
Dirk K Morr Nikolaos A Stavropoulos

We study the electronic structure of magnetic and nonmagnetic quantum corrals embedded in two-dimensional s-wave superconductors. We demonstrate that a quantum mirage of an impurity bound state is projected from the occupied into the empty focus of a nonmagnetic quantum corral via the excitation of the corral's eigenmodes. We show that quantum corrals provide a new tool for manipulating the int...

2013
Ahmet Ali Yanik Gerhard Klimeck Supriyo Datta

A quantum transport model incorporating spin scattering processes is presented using the non-equilibrium Green's function (NEGF) formalism within the self-consistent Born approximation. This model offers a unified approach by capturing the spin-flip scattering and the quantum effects simultaneously. A numerical implementation of the model is illustrated for magnetic tunnel junction devices with...

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