Quantum transport setups

Quantum transport is performed in a dilution fridge (designed by cryoconcept) with 9 mK of base temperature, equipped with an 18T magnet. Sample holder is equipped with 25 heavily filtered dc wires (feedthrough pi filters, copper-powder filters, on-chip discrete filtering, lossy custom made shielded cables), and 2 coaxial lines with cold amplifier.

A second small dilution refrigerator enables fast cooldown from room T to 50mK in 3 hours. It runs either in an helium deward or in a cryostat equipped with a 16T magnet.

A new cryofree fridge (Bluefors) for the ERC project SUPERGRAPH (2020-2025) is now operational. It is equipped with a 12T magnet, 48 dc lines and 6 coaxial lines, two low-noise amplifiers (0.2-2GHz and 4-8 GHz), isolators, IR filters…

10 mK, 14 T  Scanning Tunneling Microscope

We have developped a hybrid AFM-STM operating at mK temperatures and up to 14 T. The AFM-STM enables us to scan large surfaces in AFM mode on insulating substrate in order to locate nanodevices, and then switch to STM mode on conductive surfaces to perform tunneling spectroscopy. Two different setups are operating in a low-loss helium cryostat equipped with a 14 teslas, 100 mm cold bore superconducting solenoid: i) a home-made 4K insert working with exchange gas, and ii) a custom-designed UHV dilution unit (designed by Cryoconcept)  cooling down to 0.02 K base temperature coupled to a UHV chamber for tip and sample preparation.

Lab construction

STM dil. fridge setup

Technical support

Frédéric Gay, Philippe Plaindoux (cryogeny and electronics), Didier Dufeu and Pôle ingénierie expérimentale, Daniel Lepoittevin (dedicated current-voltage converters), Sylvain Dumont (high stability DACs), SERAS, Dominique Grand (CAD engineering of STM experiment, UHV dilution fridge and preparation chamber) and many others.