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© Tim Althuon

Mechan­i­cal manip­u­la­tion of molec­u­lar spins in CNT resonators

Tim Althuon – Hector Fellow Wolfgang Wernsdorfer

Carbon nanotube (CNT) resonators will be designed and fabri­cated to exploit their sensing proper­ties. We will graft a single-molecule magnet (SMM) on such a CNT resonator in order to manip­u­late its spin states via the mechan­i­cal motion of the CNT. Using this nanome­chan­i­cal approach, single-molecule magnets will be inves­ti­gated with the long-term prospect of apply­ing them in future quantum technologies.

Build­ing a functional quantum computer is one of the most ambitious techno­log­i­cal goals of our century. A key challenge consists in finding quantum systems that are suffi­ciently protected from the environ­ment while being easily acces­si­ble. As a promis­ing candi­date, single-molecule magnets (SMMs) will be the object of this project.

Strong spin-phonon coupling between molec­u­lar spins and the mechan­i­cal motion in carbon nanotube (CNT) resonators will be exploited to perform coher­ent manip­u­la­tions of nuclear spin states in molec­u­lar magnets. The basic platform (cf. figure 1) consists of a suspended CNT which is contacted by source and drain electrodes, while mechan­i­cal motion can be driven by multi­ple capac­i­tively coupled gate electrodes. A SMM grafted on a suspended CNT can then be used to inves­ti­gate differ­ent proper­ties of molec­u­lar magnet­ism. First, the direct electri­cal manip­u­la­tion of molec­u­lar spin states in CNT resonators could be studied with the prospect of achiev­ing long relax­ation and decoher­ence times due to the mechan­i­cal isola­tion from the substrate. Second, follow­ing the strat­egy of cavity-QED exper­i­ments, where the state of an atom is manip­u­lated and read-out using cavity photons, in this work CNT phonons could be used to manip­u­late and read-out nuclear spins of SMMs.

This project adresses funda­men­tal physi­cal questions regard­ing molec­u­lar magnet­ism, whereas on the other hand, it can provide a first step towards quantum technolo­gies based on SMMs.

Mechanische Manipulation molekularer Spins in CNT Resonatoren

Figure 1: Single-molecule magnet (red arrow: magne­ti­za­tion axis) grafted on suspended CNT. V_SD: applied bias between source and drain, V_G1,...,V_G5: bias applied to gate electrodes 1 to 5, I: measured current through the CNT.

Tim Althuon

Karlsruhe Insti­tute of Technology

Super­vised by

Prof. Dr.

Wolfgang Werns­dor­fer

Physics & Chemistry

Disziplinen Wolfgang WernsdorferHector Fellow since 2019