arXiv subjects

Andrea Huck

Publications and source records attributed to Andrea Huck.

3 recordsLinked to original sources

arXiv1997

Influence of Quantum Fluctuations on Phase Coherent Andreev Tunneling

We study the subgap transport properties of a small capacitance normal metal-superconductor tunnel junction coupled to an external electromagnetic environment. Mesoscopic interference between the electrons in the normal metal strongly enhances the subgap conductance with decreasing bias voltage. On the other hand, quantum fluctuations of the environment destroy electronic phase coherence and suppress the subgap conductance at low bias (Coulomb blockade).The competition between charging effects and mesoscopic interference leads to a non-monotonic dependence of the differential subgap conductance on the applied bias voltage. This feature is pronounced, even if the coupling to the environment is weak and the charging energy is small.

cond-mat.mes-hall↗

arXiv1997

Time Reversal Symmetry Breaking and Spontaneous Currents in s-Wave / Normal Metal / d-Wave Superconductor Sandwiches

We study the physical properties of an $s$-wave -- normal metal -- $d$-wave junction in terms of the Andreev bound states in the normal metal layer. The phase dependence of bound states with different orientations leads to superconducting states with broken time reversal symmetry for generic orientations of the $d$-wave superconductor crystal. The occurrence of such a state and the associated spontaneous supercurrent along the junction is analyzed in the framework of Ginzburg-Landau theory and by the solution of the Bogolyubov-de Gennes equations.

cond-mat.supr-con↗

arXiv1994

Quantum Interference of Coulomb Interaction and Disorder: Phase Shift of Friedel Oscillations and an Instability of the Fermi Sea

We investigate the influence of interference between Coulomb interaction and impurity scattering on the static electronic response $χ(0,q)$ in disordered metals to leading order in the effective Coulomb interaction. When the transport relaxation time $τ_{tr}$ is much shorter than the quasiparticle life time, we find a $\mbox{sgn}(2p_F-q)/\sqrt{|2p_F-q|}$ divergence of the polarization function at the Fermi surface ($q=2p_F$). It causes a phase shift of the Friedel oscillations as well as an enhancement of their amplitude. Our results are consistent with experiments and may be relevant for understanding the stability of the amorphous state of certain alloys against crystallization.

cond-mat↗