Domain, Specialties : Condensed matter physics
Keywords: spin electronics, supercurrents, itopological insulators
Research Unit : SPEC / LNO
Summary
The aim of this internship is to develop a system for detecting supercurrents in topological insulators using Giant Magneto-Resistance (GMR) devices, whose low-temperature sensitivity will give access to these fluctuations at the local level.
Full description
This topic is funded by the ANR TirDhel project, in collaboration with the Laboratoire de Physique des Solides and C2N.
We have already developed a highly sensitive technique for detecting orbital current in graphene, based on GMRs (giant magnetoresistance sensors) [Fermon2017]. We are already reaching a sensitivity of 1 nT/VHz due to an intrinsic resistance noise of 3 μΩ/Hz of the GMR [Vallejo, Science 2021].
The general idea is to combine a cryogenic amplifier designed by C2N and adapted to GMR sensors in order to detect supercurrent fluctuations in a topological material. We plan to start measurements at low frequencies (kHz), where the sensitivity of the GMR and amplifiers should enable us to measure the noise spectrum. The sensors thus developed at SPEC will be used by the LPS to measure various topological materials (Bi, WTe2 and possibly Bi4Br4 nanowires) on which edge states have been demonstrated.
The internship will involve designing and building GMRS sensors adapted to the problem of measuring topological systems in cryogenic environments. These sensors will first be tested in the laboratory at room temperature, then at the LPS at low temperatures, before being integrated into a complete system for measuring edge states.
References:
- Fermon, C., & Van de Voorde, M. (Eds.). (2016). Nanomagnetism: applications and perspectives. John Wiley & Sons.
- J. Vallejo Bustamante et al. Detection of graphene’s divergent orbital diamagnetism at the Dirac point, Science 374,1399-1402(2021).DOI:10.1126/science.abf9396
Location
CEA Saclay, 91 Essonne, France
Internship conditions
- Internship duration: 5 months
- Level of study: Bac+4/5
- Training: Master 2
- Continuation in PhD thesis: No
- Application deadline: 1 février 2025
Experimental skills
- Language : English
- Useful methods and technics: microfabrication, magneotransport, noise measurements, instrumentation
- Computer languages and software: Qtiplot, Python
Supervisor
Myriam Pannetier Lecoeur
Phone: 0169087410
Email :