Anders Rosengren

IMPURITY-INDUCED VIRTUAL BOUND STATES IN D-WAVE SUPERCONDUCTORS

It is shown that a single, strongly scattering impurity produces a bound or a virtual bound quasiparticle state inside the gap in a

Elastic Anisotropy of Earth's Inner Core

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Origin of the low rigidity of the Earth's inner core

-wave superconductor. The explicit form of the bound state wave function is found to decay exponentially with angle-dependent range. These states provide a natural explanation of the second Cu NMR rate arising from the sites close to Zn impurities in the cuprates. Finally, for finite concentration of impurities in a

Localized Spin Ordering in Kondo Lattice Models

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Impurities and quasi-one-dimensional transport in a d-wave superconductor.

-wave superconductor, we reexamine the growth of these states into an impurity band, and discuss the Mott criterion for this band.

Study of the Blume-Emery-Griffiths model on the triangular lattice by the cluster-variation method

Earths solid-iron inner core is elastically anisotropic. Sound waves propagate faster along Earths spin axis than in the equatorial plane. This anisotropy has previously been explained by a preferred orientation of the iron alloy hexagonal crystals. However, hexagonal iron becomes increasingly isotropic on increasing temperature at pressures of the inner core and is therefore unlikely to cause the anisotropy. An alternative explanation, supported by diamond anvil cell experiments, is that iron adopts a body-centered cubic form in the inner core. We show, by molecular dynamics simulations, that the body-centered cubic iron phase is extremely anisotropic to sound waves despite its high symmetry. Direct simulations of seismic wave propagation reveal an anisotropy of 12%, a value adequate to explain the anisotropy of the inner core.

On the Ising model for the simple cubic lattice

Earths solid-iron inner core has a low rigidity that manifests itself in the anomalously low velocities of shear waves as compared to shear wave velocities measured in iron alloys. Normally, when estimating the elastic properties of a polycrystal, one calculates an average over different orientations of a single crystal. This approach does not take into account the grain boundaries and defects that are likely to be abundant at high temperatures relevant for the inner core conditions. By using molecular dynamics simulations, we show that, if defects are considered, the calculated shear modulus and shear wave velocity decrease dramatically as compared to those estimates obtained from the averaged single-crystal values. Thus, the low shear wave velocity in the inner core is explained.

On temperature broadening in X-ray spectra of metals

Using a non-Abelian density matrix renormalization group method we determine the phase diagram of the Kondo lattice model in one dimension, by directly measuring the magnetization of the ground state, This allowed us to discover a second ferromagnetic phase missed in previous approaches. The phase transitions are found to be continuous. The spin-spin correlation function is studied in detail, and we determine in which regions the large and small Fermi surfaces dominate. The importance of double-exchange ordering and its competition with Kondo singlet formation is emphasized in understanding the complexity of the model.

Ab Initio Study of Water Interaction with a Cu Surface

Impurity scattering in the unitary limit produces low energy quasiparticles with anisotropic spectrum in a two-dimensional

Phase diagram of the 1D Kondo lattice model

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