Laboratory for Topological Quantum Phenomena in Superconductive Systems

• Our researchers have implemented the Josephson effect in junctions based on topological superconductors and ferromagnetic materials.
• We have developed the theory of superconductive hybrid structures. Experimental research has been conducted using scanning tunnel spectroscopy and atomic force microscopy as well as high precision low temperature transport measurements.
• Our researchers have developed methods to produce of memory elements based on controlled superconductor-ferromagnetic Josephson structures and studied the Josephson effect in superconductor – nanowire systems.
• By using low temperature magnetic force microscopy and decorating by ferromagnetic nanoparticles we have for the first time researched the structure of the magnetic flow on the surface of ferromagnetic conductor EuFe2(As1−xPx)2. We have demonstrated spontaneous generation of vortex antivortex quantum pairs and phase transition in domain vortex antivortex state. We have developed a quantitative theory of this phenomenon and suggested a new way to implement superconductive superlattices that give unprecedented opportunities for developing superconductive hybrid structure physics.
• Using scanning tunnel spectroscopy we have shown the possibility of implementing Abrikosov vortices in thin layers of non-superconductive metal (Cu) in the Cu/Nb hybrid structures. The discovered effect broadens the understanding of the nature of the proximity effect in superconductive structures and opens new possibilities for practical applications of in electronic devices.
• We have proposed and studied a sensitive method to research ferromagnetic resonance and corresponding magnetic qualities of separate microscale ferromagnetic samples as well as samples of weak ferromagnetic alloys.
• For the first time we have conducted observations of superconductivity induced by the proximity effects in the BiSb Dirac semimetal. We have discovered 4π-periodicity of Andreev bound states and supercurrent in Nb-BiSb-Nb Josephson junctions. Usage of topological volume characteristics of a polymetal makes devices less sensitive to surface disorder and degradation. Obtained results make up a platform to research a new type of superconductivity and symmetry of order parameters in topological materials and open a new path to topological quantum computations.

Implemented results of research: A patent «A method to produce devices with submicron Pi Josephson junction» №o 599904 has been acquired on 29.06.2015, Author: V.S. Solyarov

Education and career development:

• 4 candidate dissertations, 8 masters dissertations, 7 bachelors dissertations have been defended.
• We have conducted 1 conference and 2 International schools for young scientists «Superconductive hybrid nanostructures: physics and applications».
• Internships have been organized in our research domain in leading international research institutions.
• Internships for young researchers from Russian and foreign organizations at the Laboratory have been organized.
• We have developed and implemented over 10 lecture courses and case studies.
• Monograph «Macroscopic quantum electronics: from basics to applications. A textbook of questions and problems» authored by N. Klyonov, S. Bakurskiy, I. Solovyov.

Organizational and structural changes:

We have organized a laboratory equipped with unique equipment including a SPECs low temperature ultra-high vacuum tunnel microscope, a AFM/MFM AttoDRY100 atomic force/magnetic force microscope, and a Blue-Force refrigerator

Collaborations:

Nagoya University (Japan), Hokkaido University (Japan), Argonne National Laboratory (USA), Institute of Nanophysics (France), University of Twente (the Netherlands): joint research and scientific events