Biomedical subjects

Bernhard Kramer

Publications and source records attributed to Bernhard Kramer.

2 recordsLinked to original sources

PubMed2006

Electron correlations and single-particle physics in the integer quantum Hall effect.

The compressibility of a two-dimensional electron system with spin in a spatially correlated random potential and a quantizing magnetic field is investigated. Electron-electron interaction is treated with the Hartree-Fock method. Numerical results for the influences of interaction and disorder on the compressibility as a function of the particle density and the strength of the magnetic field are presented. Localization-delocalization transitions associated with a highly compressible region in the energy spectrum are found at half-integer filling factors. Coulomb blockade effects are found near integer fillings in the regions of low compressibility. Results are compared with recent experiments.

Journal Article↗

PubMed2006

Dynamics of a domain wall and spin-wave excitations driven by a mesoscopic current.

The dynamics of a domain wall driven by a spin-polarized current in a mesoscopic system is studied numerically. Spin mixing in the states of the conduction electrons is fully taken into account. When the Fermi energy of the electrons is larger than the exchange energy (E(F) > J(sd)), the spin precession induces spin-wave excitations in the local spins which contribute towards the displacement of the domain wall. The resulting average velocity is found to be much smaller than the one obtained in the adiabatic limit. For E(F) < J(sd), the results are consistent with the adiabatic approximation except for the region below the critical current where a residual domain wall velocity is found.

Journal Article↗