Training

Tristan BERANGER

Theses in preparation in Montpellier , as part of the École Doctorale Information, Structures, Systèmes , in partnership with IES - Institut d'Electronique et des Systèmes (laboratory) and MOdélisation et Spectroscopie TéraHertz (MoST) (research team) .

Co-supervisors: Dr. J. Torres (IES) and Dr. S. Ruffenach (L2C)

This project is part of the LINkS consortium, funded by the European Commission under the H2020 program and involves top partners from cell biology, biochemistry, theoretical biophysics and nanotechnology groups as well as SMEs. It is a scientifically challenging project which plans to change the paradigms of the self-organization of the intracellular living matter with a radical new vision of protein-protein attractive mechanisms. It will develop a radically new breakthrough technology of lab-on-a-chip THz-biosensor.

We seek to lay the foundations of a new technology, which will allow the study of intermolecular electrodynamic forces in the real complexity of biological systems and, in the long term, address proteomic analysis, biomarker identification and associated personalized therapies.

Maria SZOŁA

Transnational co-tutored thesis, as part of IRP TERAMIR

Laboratories : L2C, Universite Montpellier, France - IHPP -PAS, Poland

Co-supervisors: Dr. F. Teppe (L2C) and Dr. G. Cywinski (IHPP PAS)

Dirac matter is a newly discovered class of condensed matter system, described by the Dirac equation. Distinguished examples are topological insulators, graphene or Weyl semimetals. It appears as if HgCdTe would also be a good candidate while its bandgap Eg = 0 at some concentration of Cd, temperature of pressure. Then, HgCdTe becomes similar to graphene where electrons act as 2D massless fermions with zero-bandgap conical bands.

Main aim of this research is to observe a phase transition between semimetal and semiconductor phase in HgCdTe, bulk materil and HgTe quantum wells. This transition would be induced by the hydrostatic pressure applied to the sample. To obsevrve it, a THz transmission through the samples in the magnetic field will be investigated.

In order to analyze obtained data theimplified Kane model will be used and if necessary a new model, containing a contribution from the hydrostatic pressure will be developed.

This research will give the opportunity to investigate spectral properties of THz excitations of two-dimensional gas of massless Dirac fermions.

Sebastien GEBERT

PhD position in the EU Horizon 2020 Marie Skłodowska-Curie MSCA-ITN Project TeraApps (Doctoral Training Network in Terahertz Technologies for Imaging, Radar and Communications Applications)

This thesis is an investigation of the Terahertz/Infrared emission and absorption spectroscopy of various Dirac materials in magnetic fields. The studied materials reach from graphene over different topological insulators (TIs) to novel Dirac-/Weyl-semimetals.

The experimental results and complementary theoretical calculations show, that the emission, arising in the incipient Landau quantization regime, is favored both by the finite rest-mass and the specific band dispersion of HgTe QWs. The latter breaks the series of equidistantly spaced LL subsets and thus suppresses non-radiative Auger recombination inherent in graphene. At the same time and against all expectations, an emission signal was also observed from some graphene samples. Finally, some emission has also been obtained from Dirac-/Weyl-semimetals.

The preliminary results show that the emission may be linked to the semi-classical CR, but deeper analysis is needed to confirm these first results and understand this phenomenon.

Yoann MERIGUET

This project proposes to develop new biological sensors at terahertz (THz) frequencies based on low-cost field-effect transistors (LC-FETs) and specially designed transistors with silicon nanowires (NW-FETs). The development of these sensors working in conditions close to the physiological environment will take place from a unique multidisciplinary point of view involving theoretical and experimental physicists, molecular biologists and electronic engineers working on theory, manufacturing, experiments and numerical simulations.

These biosensors will make it possible to determine the spectral signatures of proteins either in aqueous medium (near-field) or in powder form (far-field), whose response is generally unobservable due to the strong absorption of water in this spectral range. The design, manufacture and characterization of these reliable and highly sensitive biosensors will open up new avenues for non-drug medical action and sustainable management of environmental resources (water, public health).

Anastasiia KUDASHOVA

PhD position in the EU Horizon 2020 Marie Skłodowska-Curie MSCA-ITN Project TeraApps (Doctoral Training Network in Terahertz Technologies for Imaging, Radar and Communications Applications)

There are a number of techniques available for recording in-situ water content profiles over time, such as X-ray tomography or nuclear magnetic resonance (NMR). These techniques are currently being applied to wood samples, but they are tricky to implement, not least because of the ionizing nature of the beam used to scan the sample. A technique using a non-ionizing Tera-Hertz (THz) beam is currently being researched by the "Spectroscopie Térahertz" team at the Charles Coulomb Laboratory (University of Montpellier). As part of a thesis on the wood used to make clarinets, and in collaboration with the wood team of the Laboratoire de Mécanique et Génie Civil (University of Montpellier), preliminary tests using this technique on wood were carried out. Unfortunately, the confinement did not allow full use to be made of the device developed.

The aim of this PFE is therefore to finalize the experimental set-up, calibrate the measurements, carry out water diffusion experiments in poplar samples and compare the results obtained with conventional "weighing" measurements and numerical diffusion simulations based on literature data.

We recently demonstrated that proteins undergo global oscillations and resonate at certain specific frequencies. This discovery suggests that cellular proteins could communicate at a distance via wireless antennas. If this were the case, our data would open up a new field of investigation for the study of the biological functions of proteins, in particular for the analysis of the regulation of protein-protein interactions.With this project, we are starting a program of spectral characterization of a protein sample in order to create a database. The ultimate aim is to confirm the existence of wireless electromagnetic signals that enable inter-protein communication, and ultimately to identify ways of modulating these signals to regulate the function of proteins involved in the development of certain pathologies.

Agriculture in France uses 3 billion m3 of water for irrigation, and wastes over 30% of it every year. To limit water wastage for agricultural use, it is necessary to know when crops need watering. We have studied a solution using THz waves to determine a plant's water content. Depending on the plant's water content, it is possible to determine its need for water. However, THz waves are still little-known and still being studied. During this internship, we measured the transmission of THz waves by several leaves