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Q-NET young researchers

Anna FESHCHENKO
Low Temperature Laboratory, O. V. Lounasmaa Laboratory, Aalto University, Helsinki, Finland
Female, Russian

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Diplomas, University(ies)
puce
Master’s Degree in Science and Technology. Lappeenranta University of Technology, Lappeenranta, Finland (2010 – 2011).

puce
Master’s Degree in Science and Technology. St. Petersburg Electrotechnical University “LETI”, St. Petersburg, Russia (2009 – 2011).
Master’s thesis: “Improving the quality of aluminium oxide tunnel junctions by thermal annealing”.
The main goal of this Master’s Thesis work was to characterize the improvement of the quality of aluminium oxide tunnel junctions by thermal annealing.
Technologies of sample fabrication and thermal annealing are described in the thesis.
The electrical measurement techniques, used to assess the junction quality and results obtained from measurements are illustrated.
Observed differences between annealed and not annealed junctions are shown.
After the annealing process, junction aging was significantly reduced, the barrier was found to be more uniform, its height increased.
Reduction of resistance noise was also observed, but charge noise increased.

puce Bachelor's Degree in Science and Technology. St. Petersburg Electrotechnical University “LETI”, St. Petersburg, Russia (2005 –2009).
Bachelor thesis: “Growth and Study of 3C-SiC Epitaxial Layers Produced by Sublimation Epitaxy in Vacuum on 15R-SiC Substrates”.

Field of research
Fabrication of nanodevices based on tunnel junctions, transport measurements at sub-kelvin temperatures, Coulomb blockade thermometry

Research experience
hjg Jan 2011 – May 2011: Low Temperature Laboratory, Aalto University, Helsinki, Finland. Master Thesis student. Fabrication and measurements of single and double Al/AlOx/Al junctions (single electron transistor), to observe the improvements of quality after thermal annealing process

hjg Sep 2008 – May 2010: Laboratory of Physics of Semiconductor Devices, Ioffe Physical-Technical Institute of the Russian Academy of Sciences, St. Petersburg, Russia. Bachelor Thesis student and after as a Master student. Growth and study of SiC epitaxial layers produced by sublimation epitaxy in vacuum

hjg 2008:Photovoltaics Laboratory, Ioffe Physical-Technical Institute of the Russian Academy of Sciences, St. Petersburg, Russia. Summer student (Bachelor). Study the basic principles of photovoltaic conversion of solar energy, structure and design of photovoltaic modules with radiation concentrators, methods of measuring the characteristics of their basic elements

Thesis Project : Title, Summary
“Single-electron devices and quantum metrology”

This project focuses on metrological use of nanosized tunnel junction devices. In our days an interesting task in modern metrology is to build a quantum current standard, which will allow closing the so-called metrological triangle. A missing piece in closing this triangle is an accurate current source. It has recently been suggested [1] that, a double-junction geometry in form a single-electron transistor between superconducting and normal electrodes, meaning a SINIS structure, can be used for development of a quantum current standard based on the discreteness of the charge; current is carried by individual electrons of charge e. A device, that can transfer a number n of electrons at frequency f would be used as a current standard with magnitude I = nef [2], [3]. Earlier experiments have demonstrated current with a relative uncertainty in the 10−8 range [4], but at picoampere level only. SINIS turnstile [1] can produce quantized output current exceeding 100 pA with relatively the same accuracy, by using few devices in parallel. In this project I would implement new fabrication techniques in order to produce improved SINIS current turnstiles. The remaining error sources will be studied and then hopefully reduced. A structure, where the errors of the current turnstiles can be directly measured, is represented in Figure 1. The main part of my thesis work is related to measurement techniques, in particular monitoring individual electron transfer error events by direct single-electron counting techniques, and suppressing them by choosing the correct parameters of the device, and careful filtering of the system.

Description : Current detector

Figure 1: A structure for measuring the errors of electron pumping in a configuration that consists of two SINIS turnstiles and an SET, which is used as a current detector.

Recently, it has been found that the processes which need to be controlled in order to achieve high accuracy in synchronized charge pumping are Andreev (two-electron) current, and Cooper-pair – electron co-tunneling [5], photon-assisted tunneling, and quasiparticle processes of a nonequilibrium superconductor.

The development of a current standard based on the SINIS single-electron transistor is the main task of this research project.

 

References                    
[1] J. P. Pekola, J. J. Vartiainen, M. Möttönen, O. - P. Saira, M. Meschke, et al., Hybrid single-electron transistor as a source of quantized electric current, Nature Phys. 4, 120–124 (2008)
[2] D. V. Averin, K. K. Likharev, in SQUID’85: Superconducting quantum interference devices and their applications, edited by H. D. Hahlbohm and H. Lubbig (deGruyter, Berlin, 1986), p. 345
[3] D. V. Averin and K. K. Likharev, Mesoscopic Phenomena in Solids (Elsevier, Amsterdam, 1991), pp. 173–271
[4] Keller, M. W., Martinis, J. M., Zimmerman, N. M. and Steinbach, A. H., Accuracy of electron counting using a 7-junction electron pump, Appl. Phys. Lett. 69, 1804 – 1806 (1996)
[5] D. V. Averin and J. P. Pekola, Phys. Rev. Lett. 101, 066801 (2008)

List of Publications
"Improving the quality of aluminium oxide tunnel junctions by thermal annealing”, Master’s Thesis, Lappeenranta University of Technology, 2011.

[Feshchenko]"Primary Thermometry in the Intermediate Coulomb Blockade Regime" A. V. Feshchenko, M. Meschke, D. Gunnarsson, M. Prunnila, L. Roschier, J. S. Penttilä, J. P. Pekola Temp. Phys., published on-line April 2013, DOI 10.1007/s10909-013-0874-x, Task 3.1.

Primary thermometry in the intermediate Coulomb blockade regime, A. V. Feshchenko, M. Meschke, D. Gunnarsson, M. Prunnila, L. Roschier, J. S. Penttilä and J. P. Pekola, Journal of Low Temperature Physics 173, 36 (2013).

Experimental realization of a Coulomb blockade refrigerator, A. V. Feshchenko, J. V. Koski, J. P. Pekola, Physical Review B 90, 201407(R) (2014).

Tunnel-Junction Thermometry Down to Millikelvin Temperatures, A. V. Feshchenko, L. Casparis, I. M. Khaymovich, D. Maradan, O. P. Saira, M. Palma, M. Meschke, J. P. Pekola, D. M. Zumbuehl, Physical Review Applied 4,  034001 (2015).

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