The vortex dynamics of a Ginzburg-Landau system under pinning effect

It is proved that the vortices are attracted by impurities or inhomogeities in the superconducting materials. The strong H^1-convergence for the corresponding Ginzburg-Landau system is also proved.Comment: 23page

Magnetophoresis of nonmagnetic particles in ferrofluids

Ferrofluids containing nonmagnetic particles are called inverse ferrofluids. On the basis of the Ewald-Kornfeld formulation and the Maxwell-Garnett theory, we theoretically investigate the magnetophoretic force exerting on the nonmagnetic particles in inverse ferrofluids due to the presence of a nonuniform magnetic field, by taking into account the structural transition and long-range interaction. We numerically demonstrate that the force can be adjusted by choosing appropriate lattices, volume fractions, geometric shapes, and conductivities of the nonmagnetic particles, as well as frequencies of external magnetic fields.Comment: 24 pages, 7 figure

Oscillatory Magneto-Thermopower and Resonant Phonon Drag in a High-Mobility 2D Electron Gas

Experimental and theoretical evidence is presented for new low-magnetic-field ($B<5$ kG) 1/B-oscillations in the thermoelectric power of a high-mobility GaAs/AlGaAs two-dimensional (2D) electron gas. The oscillations result from inter-Landau-Level resonances of acoustic phonons carrying a momentum equal to twice the Fermi wavenumber at $B = 0$. Numerical calculations show that both 3D and 2D phonons can contribute to this effect.Comment: 4 pages, 5 figure

Boundary effect on CDW: Friedel oscillations, STM image

We study the effect of open boundary condition on charge density waves (CDW). The electron density oscillates rapidly close to the boundary, and additional non-oscillating terms (~ln(r)) appear. The Friedel oscillations survive beyond the CDW coherence length (v_F/Delta), but their amplitude gets heavily suppressed. The scanning tunneling microscopy image (STM) of CDW shows clear features of the boundary. The local tunneling conductance becomes asymmetric with respect to the Fermi energy, and considerable amount of spectral weight is transferred to the lower gap edge. Also it exhibits additional zeros reflecting the influence of the boundary.Comment: 7 pages, 6 figure

Coupled electron and phonon transport in one-dimensional atomic junctions

Employing the nonequilibrium Green's function method, we develop a fully quantum mechanical model to study the coupled electron-phonon transport in one-dimensional atomic junctions in the presence of a weak electron-phonon interaction. This model enables us to study the electronic and phononic transport on an equal footing. We derive the electrical and energy currents of the coupled electron-phonon system and the energy exchange between them. As an application, we study the heat dissipation in current carrying atomic junctions within the self-consistent Born approximation, which guarantees energy current conservation. We find that the inclusion of phonon transport is important in determining the heat dissipation and temperature change of the atomic junctions.Comment: 10 pages, 7 figure