Investigations of the band line-up in semimetallic InAs---GaSb superlattices under hydrostatic pressure

Using magneto-optical methods, we have measured the energy separation between the subbands in a semimettalic InAs---GaSb superlattice associated with the InAs conduction band (CB) and the GaSb valence band (VB) as a function of hydrostatic pressure up to 11kBar. The CB-VB energy overlap (Δ) at the InAs---GaSb interface is found to depend less on pressure than predicted on grounds of usual assumptions concerning band energy shifts induced by pressure.Also inter-subband coupling has been observed between the bands in different adjacent materials. This coupling is found to lead to anti-crossing in the subband dispersion relation.     

Freie Weglängen im supraleitenden Zustand,im normalen Zustand und im Zwischenzustand

By size-effect measurements of the thermal conductivity of thin indium wires the mean free path of the excitations has been determined in the normal and in the superconducting state. Within the accuracy of these measurements, the mean free paths in the two states are found to be equal. — For the intermediate state the electron scattering from the interphase boundaries has been investigated both experimentally and theoretically. The experimental results can be explained with the aid of theBardeen-Cooper-Schrieffer theory of superconductivity.     

Magnetoelectric anisotropy in diffusive transport

In this Letter we prove the existence of a new general diffusive transport phenomenon in crossed electric and magnetic fields: magnetoelectric anisotropy. For the specific case of diffusive electrical transport, we present a relativistic model to quantify this effect and present experimental evidence for its existence.     

Modeling of the Dielectric Breakdown Under Strong Magnetic Fields

The formation of breakdown pattern on an insulating surface under the influence of a transverse magnetic field is theoretically investigated. We have generalized the Dielectric Breakdown Model (DBM) and random walker model for the case of external magnetic field. It is shown that fractal dimensionality of the discharge saturates with magnetic fields. It is conjectured that nonlinear current interaction is responsible for the experimentally observed spider-legs like streamer patterns.     

Photon assisted tunneling in superconductor-normal metal point contacts at far-infrared frequencies

The response of normal metal-superconductor point contacts to radiation at frequencies up to 2.5 THz is studied experimentally. The results can be analyzed in terms of the so called Photon Assisted Tunneling (PAT) effect and are in excellent agreement with recent theoretical predictions.     

Ring-shaped vortex domain in type-II superconductors

We present results of experiments in superconducting niobium and numerical simulations showing the creation of a metastable ring-shaped vortex domain by heating. Such vortex rings, if pinned by structural defects, can exist forever.