نتایج جستجو برای: impurity
تعداد نتایج: 9919 فیلتر نتایج به سال:
Nanoscale physics and dynamical mean-field theory have both generated increased interest in complex quantum impurity problems and so have focused attention on the need for flexible quantum impurity solvers. Here we demonstrate that the mapping of single-quantum impurity problems onto spin chains can be exploited to yield a powerful and extremely flexible impurity solver. We implement this clust...
Using a nonequilibrium density functional calculation, we investigated the electronic transport properties and fundamental mechanism of spin polarization as a function of the location of impurities from the center to an edge of a graphene nanoribbon device (GND) with zigzag edges. A center-located impurity enables both edges to be enhanced with respect to their spin transports whereas an edge-l...
We present a new simplified derivation of the effect of lattice relaxation that accompanies the quantum tunneling of 3He impurities in solid 4He on the nuclear spin-lattice relaxation of the 3He impurities for very low impurity concentrations. As a result of the larger zero point motion of the 3He impurity compared to the 4He atoms, a significant lattice distortion accompanies the impurity as i...
The STM tunneling through a quantum wire (QW) with a side-attached impurity (atom, island) is investigated using a tight-binding model and the nonequilibrium Keldysh Green function method. The impurity can be coupled to one or more QW atoms. The presence of the impurity strongly modifies the local density of states of the wire atoms, thus influences the STM tunneling through all the wire atoms....
Investigation of impurity transport properties in tokamak plasmas is essential and a diagnostic that can provide information on the impurity content is required. Combining charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES), absolute radial profiles of impurity densities can be obtained from the CXRS and BES intensities, electron density and CXRS and BES emiss...
We study the efFect of an isolated impurity on the low-energy properties of a half-odd-integerspin Heisenberg antiferromagnetic chain using both numerical and conformal field theory techniques. The impurity corresponds to the substitution of a magnetic ion by a difFerent ion with the same or different spin, or else to the coupling of a magnetic impurity to a single spin on the chain. Depending ...
The transport of intrinsic impurities is investigated during standard and improved confinement regimes of the Madison Symmetric Torus (MST) reversed-field pinch. The impurity diffusion coefficient (D) and pinch velocity (v) are obtained through comparing the time evolution of experimental impurity density profiles with the results of a one-dimensional impurity transport code. Experimental hollo...
We study the low-temperature thermodynamics of a spin-S magnetic impurity coupled to m>2 degenerate bands of interacting electrons in one dimension. By exploiting boundary-conformal-field-theory techniques, we derive exact results for the possible impurity thermal and magnetic response. The leading behavior of the impurity magnetic susceptibility is shown to be insensitive to the electron-elect...
We study the low-temperature properties of a spin2 magnetic impurity coupled to a one-dimensional interacting electron system. Using the newly developed formalism by Affleck and Ludwig, with a scale invariant boundary condition replacing the impurity, we exploit boundary conformal field theory to deduce the impurity thermal and magnetic response. In the case of only forward electron scattering ...
People sometimes report feeling “totally” different (complete affectedness) and that “they’ll never be the same again” (continual affectedness) after negative events. It’s been proposed that complete, and continual negative effects characterize contamination or impurity. Meanwhile, whether impurity is a legitimate moral domain apart from harm has been debated in moral psychology. We address the...
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