Our reserach group has a strong experience in quantum transport in low dimensional systemls and hybrid organic/inorganic systems.
Micro- and nano-fabrication
Thanks to the cleanroom of the MPQ lab (Fig. 1), we can fabricate our quantum devices with standard techniques such as e-beam and optical lithography, thin film evaporation of different materials (insulator, metals, semiconductors and superconductors) and dry and wetetching. We have also at disposal an atomic force microscope to characterize the surface of our thin films.
Figure 1 : Photolithography room of the clean-room at the MPQ lab
Measurements
Probe station
For quick electrical characterizations at room temperature of our devices, the team uses a probe station (Fig. 2) for AC and DC electrical measurements. We can measure current-voltage characteristics and differential conductance of our devices by adding a gate voltage at room temperature.
Figure 2 : Probe station for electronic transport measurements at room temperature.
Nextron probe station
We dispose of two compact micro probe stations (MPS) by Nextron company (www.microprobestation.com/nextronci.html) (Fig. 3).
The first MPS is equipped with 8 probes and it is suitable for in-situ transport measurements. The second MPS is equipped with 13 probes and it is suitable for in-situ transport and thermoelectric measurements. Both chamber works under vacuum or in controlled atmosphere in the temperature range 300 to 750K and are equipped by an optical access.
Figure 3 : Multi-probe stations for electric and thermoelectric measurements under vacuum or controled atmosphere
RF measurements
We have a set-up with electromagnet for RF spin pumping (Fig. 3). This method makes it possible to excite the resonance modes (magnons) of the magnetization of a thin ferromagnetic layer in contact with a low-dimensional material.
Figure 3 : Set-up for RF spin pumping
Cryogenics
Montana Cryostat
Figure 4 : Montana cryostat with optical set-up. Rotating sample holder.
VTI Cryovac
We dispose of a Variable Temperature Insert (VTI) by Cryovac (www.cryovac.de) (Fig. 5). It owns an insert with 24 independent twisted lines for DC measurements. The VTI is designed to be inserted into a standard 100-L liquid He dewar. An impedance valve and a local heater allows regulation of the pumped liquid He allowing to reach a base temperature of 1.3K. The sample can be in He atmosphere or in vacuum.
Figure 5 : Variable temperature insert pour des mesure de transport DC à 1.3K
Our equipments are in constant evolution in order to perform our latest research.