Nanoelectromechanical systems (NEMS) coupled to a single-molecule magnet: Application to study the angular momentum conservation and nano-magnetometry

• Applicant: Professor Dr. Wolfgang Wernsdorfer, Ph.D.
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 387202136

Carbon nanotubes (CNT) have become an essential building block for nanoelectromechanical systems (NEMS). Their low mass and high Young's modulus give rise to high oscillation frequencies, therefore enabling ground-state cooling with state-of-the-art cryogenics and a large zero point motion in the quantum regime. Moreover, the strong coupling between nanomechanical motion and single-electron tunnelling in high-Q CNT NEMS allows electronic actuation and detection of the nanomechanical motion. As such, CNT NEMS can be used for ultrasensitive mass sensing or as magnetic torque detectors for single spin systems. Building on our experience of the last years, we propose to develop new prototype hybrid molecular devices with nanomechanical systems opening new avenues to faster readout of molecular spin states, studies of the angular momentum conservation, and non-classical states of motion.The project is divided into 3 tasks (T): Task T1 (1st year) is the basis of all other Ts and concerns the fabrication of suspended carbon nanotube (CNT) devices. We will try different methods with the aim to select the most efficient method. Task T2 (2nd year) concerns the coupling of the nanomechanical motion of a CNT to the molecular spin moment. Different deposition methods will be tested in order to find the most adequate one. We will then use the spin valve effect to detect the reversal of the magnetic moment and study in detail the conservation of the angular moment (quantum Einstein de Haas effect). In Task T3 (3rd year), we intend to use the CNT as a torque detector for spin reversal detection. This project is supported by strong collaborations with chemist groups. The main target concerns fundamental science, but applications in quantum electronics are expected in the long run.

• DFG Programme: Research Grants
• Co-Investigator: Dr. Christoph Sürgers