Grant number:
2022/04/Y/ST3/00061
(
Weave-Unisono)
Realization period:
22 Feb 2023 - 21 Feb 2026
The aim of this research grant is devoted to the out-of-equilibrium properties of superconducting nanoscopic
hybrid devices consisting of active elements, e.g., a set of semiconducting
nanowires, connected to superconducting leads. Such devices, apart from their
applications in quantum information processing and sensor technology, provide
an ideal setup to study quantum phenomena in controlled conditions. Using
complementary methods previously developed and/or mastered by both
collaborating teams, including numerical renormalization group, diagrammatic
perturbation techniques and quantum Monte Carlo, we will evaluate linear
response properties such as thermopower or microwave response, which have
been only recently measured. Moreover, some of these methods will be further
generalized to strong out-of-equilibrium situations to provide results on AC
Josephson systems driven by finite voltage or quenched systems undergoing a
sudden change of parameters. We plan to build up a toolbox of theoretical
methods for a reliable description of nonequilibrium nanohybrids to address
both existing as well as future experiments.
International cooperation between:
Charles University in Prague (Czech Republic),
Academy of Sciences in Prague (Czech Republic),
M. Curie-Sklodowska University in Lublin (Poland),
A. Mickiewicz University in Poznan (Poland).
II. Majorana fermions in transport through correlated nanosystems
Grant number:
2018/29/B/ST3/00937
(
Opus-15)
Realization period:
2019 - 2023
The research objective of this project are the Majorana quasiparticles and their interplay with the strongly correlated low-dimensional systems. In particular, there will analyzed hybrid nanostructures composed of zero-dimensional objects e.g. single or multiple quantum dots coupled to one-dimensional topological superconductors, hosting the Majorana quasiparticles. The main aim is to develop theoretical understanding of unique signatures resulting from the Majorana quasiparticles and the strong electron correlations, predicting experimentally observable transport properties. Research tasks cover:
(i) investigation of the transport properties of the correlated double quantum dots side-coupled to the Majorana wire,
(ii) determination of cross-correlations between the quantum dots transmitted
via the topologically superconducting nanowire,
(iii) analysis of the interplay between the Majorana quasiparticles and correlations
for the quantum dot in the Kondo regime,
investigation of the polarized quasiparticles in hybrid structures
with the correlated quantum dots.
Consortium between A. Mickiewicz University (Poznan) and M. Curie-Sklodowska University (Lublin)
Prof. Ireneusz Weynmann
(Principal Investigator & Leader of the UAM node)
Prof. Tadeusz Domanski
(Leader of the UMCS node)
Postdoc positions (completed)
The previous grants:
Bound states in superconductors and interfaces
Grant number:
2017/27/B/ST3/01911
(
Opus-14)
Realization period:
29 Jun 2018 - 28 Jun 2021
Principal Investigator:
prof. Tadeusz Domanski
Recent theoretical and experimental activities focus on studying unique phenomena of the novel
materials and nanostructures, in which the proximity-induced superconducting state reveals
topological and quantum properties without analogy to any bulk system. Technological development opened
possibilities to achieve and probe such exotic superconductivity e.g. in atoms, molecules, carbon nanotubes,
nanowires and other ultra-small objects. Main subject of this research project are the Andreev/Shiba quasiparticle states, in particular:
(i) role of the bound in-gap states in multiterminal structures, focusing on
the non-local charge, spin and energy transport properties,
(i) dynamical effects (quantum quench, transient phenomena, shot-noise, waiting time distribution),
(ii) quantum phase transitions due to the subtle interplay betwee electron pairing and correlations, and
analysis of their feasible observability controlled by the electrostatic/magnetic means,
(iii) investigation of the spin-polarized Majorana quasiparticles in the topological superconductors,
(iv) charge/spin teleportation driven by the crossed Andreev scattering via the Majorana quasiparticles,
(v) role of the spin-orbit interactions in nanoscopic superconductors.
Superconductivity and correlations in nanodevices and bulk materials
Grant number:
2014/13/B/ST3/04451
Realization period:
6 Feb 2015 - 5 Feb 2018
Principal Investigator:
prof. Tadeusz Domanski
We investigate an interplay between the superconductivity and electron correlations for selected multicomponent systems, ranging from the nano- to macroscale. This issue is important for a basic science and for perspectives of applying the superconducting materials e.g. in medicine, electricity, transport, modern electronics/spintronics etc. The research aspects concern the intriguing properties and pairing mechanisms responsible for superconductivity of multiband/multiorbital materials, where strong Coulomb interactions play the crucial role. Recent interests can be also observed in the context of artificial tunneling junctions, where the superconducting leads are coupled with correlated quantum dots, forming a circuit. Role of such quantum dots could be played by: spatially confined nanoscopic electron islands, organic molecules, carbon nanotubes, semiconducting nanowires, graphene nanoflakes etc. Deep and detailed knowledge of the physics of proposed structures aimed at the identification of their functionalities is at the heart of possible applications. In experimental measurements there have been used both, the conventional (lead or vanadium) and the high temperature superconductors. Via the proximity effect the electron pairing spreads on such quantum dots. Spectacular manifestations of the induced pairing are the subgap bound states, known as the Andreev or Shiba-Yu-Rusinov states. In the case of carbon nanotubes they allowed the Josephson current to flow over macroscopic distances (whereas usually the tunneling currents decay exponentially with a width of the potential barrier). In such nanoscopic objects there are also observed the correlation effects (for instance the Coulomb blockade) competing with the induced pairing. Consequences of their competition can be observed empirically in a controllable way. In particular, there has been studied the Kondo effect (even in presence of the induced on-dot pairing) and its signatures visible in the transport (Andreev/Josephson) characteristics. In the proposed grant we shall inspect the tranport properties, considering various configurations of the heterojunctions with two or more external leads. We shall explore several geometries of the nanojunctions, in particular considering the crossed Andreev reflections (closely relative to the Cooper pair splitting). Such processes are responsible for non-local relations of the transport properties and are caused by a quantum entanglement of the electron/hole carriers.
Role of correlations, disorder and transient effects in electron systems
Grant number:
N N202 263138
Realization period:
6 Apr 2010 - 5 Apr 2013
Principal Investigator:
prof. Tadeusz Domanski
Main research tasks:
(i) Effects of inhomogeneities and correlations due to various impurities introduced
to the single- and multi-band superconductors and their influence on thermodynamic
and transport properties.
(ii) Transport properties of hetero-structures with the quantum dots,
where the repulsive Coulomb interaction is responsible for many-body
effects, such as the Kondo effect.
(iii) Precursor effects in high-Tc superconductors and
analysis of the incoherent hole pairs above the transition temperature
revealing finite-length correlations.
(iv)
Nonequilibrium processes showing up in electron transport through
the quantum dots arranged in various geometries, with special account
of the electromagnetic field impulses and/or fast modulations of
the gate potentials.