arXiv subjects

M. Baranska

Publications and source records attributed to M. Baranska.

4 recordsLinked to original sources

arXiv2020

Dynamical leakage of Majorana mode into side-attached quantum dot

We study a hybrid structure, comprising the single-level quantum dot attached to the topological superconducting nanowire, inspecting dynamical transfer of the Majorana quasiparticle onto normal region. Motivated by the recent experimental realization of such heterostructure and its investigation under the stationary conditions [L. Schneider et al., https://doi.org/10.1038/s41467-020-18540-3, Nature Communications 11, 4707 (2020)] where the quantum dot energy level can be tuned by gate potential we examine how much time is needed for the Majorana mode to leak into the normal region. We estimate, that for typical hybrid structures this dynamical process would take about 20 nanoseconds. We propose a feasible empirical protocol for its detection by means of the time-resolved Andreev tunneling spectroscopy.

cond-mat.mes-hall↗

arXiv2018

Fluctuation conductivity due to the preformed local pairs

We investigate the properties of a system where the itinerant electrons coexist and interact with the preformed local pairs. Using the nonperturbative continuous unitary transformation technique we show that Andreev-type scattering between these charge carriers gives rise to the enhanced diamagnetic response and is accompanied by appearance of the Drude peak inside the pseudogap regime ω<2Δ_{pg}. Both thes effects are caused above the transition temperature T_c by the short-range superconducting correlations. In fact, the residual diamagnetism has been detected by the torque magnetometry in the lanthanum and bismuth cuprate superconductors at temperatures up to ~ 1.5T_c. In this work we show how the superconducting correlations can be observed in the a.c. and d.c. conductivity.

cond-mat.supr-con↗

arXiv2017

Off-axis electron holography of magnetic nanostructures: magnetic behavior of Mn rich nanoprecipitates in (Mn,Ga)As system

The Lorentz off-axis electron holography technique is applied to study the magnetic nature of Mn rich nanoprecipitates in (Mn,Ga)As system. The effectiveness of this technique is demonstrated in detection of the magnetic field even for small nanocrystals having an average size down to 20 nm.

cond-mat.mtrl-sci↗

arXiv2015

Constructive influence of the induced electron pairing on the Kondo state

Superconductivity and magnetism are usually the conflicting (competing) phenomena. We show, however, that in nanoscopic objects the electron pairing may promote the magnetic ordering. Such situation is possible at low temperatures in the quantum dots placed between the conducting and superconducting reservoirs, where the proximity induced electron pairing cooperates with the correlations enhancing the spin-exchange interactions. The emerging Kondo resonance, which is observable in the Andreev conductance, can be significantly enhanced by the coupling to superconducting lead. We explain this intriguing tendency within the Anderson impurity model using: the generalized Schrieffer-Wolff canonical transformation, the second order perturbative treatment of the Coulomb repulsion, and the nonperturbative numerical renormalization group calculations. We also provide hints for experimental observability of this phenomenon.

cond-mat.supr-con↗