University of Basel, Department of Physics / Quantum Coherence Lab

Position ID:University of Basel-Department of Physics / Quantum Coherence Lab-PHD1 [#11397]
Position Title: Microkelvin Regime in Nanoelectronic Devices
Position Type:Postdoctoral
Position Location:Basel, Basel-Stadt 4056, Switzerland
Subject Areas: Physics / Condensed Matter Experiment, Condensed Matter Physics, Physics, Quantum Science
Appl Deadline:2018/09/30 finished (2018/07/10, finished 2019/04/07)
Position Description:    

*** this position has been closed, and no new applications will be accepted. ***

We are looking for a highly motivated and talented physicist with strong laboratory skills for the study of tunnel junction devices and GaAs two dimensional electron gases (2DEGs) at ultra-low temperatures, obtained by means of on-chip adiabatic nuclear demagnetization (AND).

AND is a well-established technique for cooling bulk metals down to microkelvin temperatures which has been adapted in our group for quantum transport measurements [1]. The electronic temperature is inferred from conductance measurements using metallic coulomb blockade thermometers (CBTs), reliable and precise thermometers [2] down to the low mK regime [4]. Employing on-chip AND to a CBT [3], temperatures as low as 2.8 mK were demonstrated [5], while normal metal – insulator – superconductor tunnel junctions (NIS) cooled down to 7 mK [6]. The suitable candidate will further push this limit by cooling CBT and NIS devices to below 1 mK, thus opening the door for quantum transport measurements at microkelvin temperatures. The project involves electrical transport measurements, mechanical works on a cryogen-free dilution refrigerator with adapted nuclear stage. Furthermore, the ultra-low temperature regime in GaAs 2DEGs is explored. This project involves

- Working with a dilution refrigerator adapted for AND transport experiments

- Performing transport experiments at ultra-low (world record) temperatures

- Physics of tunnel junctions, superconductors, nuclear spins (magnetic cooling), Coulomb blockade, thermal material properties at interfaces and in the bulk

- Analyzing experimental data and developing thermal models of the devices

- Presentation at international conferences and publication in high quality journals


[1] M. Palma et al., Rev. Sci. Instr. 88, 043902 (2017)

[2] J. P. Pekola et al., Phys. Rev. Lett. 73, 2903 (1994)

[3] D. I. Bradley et al., Sci. Rep. 7, 45566 (2016)

[4] D. I. Bradley et al., Nat. Commun. 7, 11678 (2016)

[5] M. Palma, C. P. Scheller et al., Appl. Phys. Lett 111, 253101 (2017)

[6] A. V. Feshchenko et al., Phys. Rev. Appl. 4, 034001 (2015)

Application Materials Required:
Submit the following items online at this website to complete your application:
And anything else requested in the position description.

Further Info:
University of Basel
Klingelbergstrasse 82
CH-4056 Basel

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