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Mandar Deshmukh - Tata Institute, Mumbai, India

Nano-electromechanical resonators to probe mesoscopic physics

Electromechanical devices are sensitive probes of mass, charge and force. An AFM is commonly used example of a resonant system that can probe extremely small surface forces. Nano electromechanical devices can also be sensitive to the internal state of the resonator. I will discuss two examples of such experiments – using monolayer grapheme resonators and resonators using nanoscale sheets of NbSe2 which undergoes a CDW transition. We use the graphene resonators to probe two questions – how does the electromechanics affect the quantum Hall state and vice versa ; these two aspects are studied by measuring the change in the resistance of the device and dispersion of the mechanical mode, respectively, as the filling factor is varied. I will discuss the results and our preliminary understanding. I will also describe experiments involving measurements on thin membranes of NbSe2. Here we observe a large change ( 10%) in elastic properties across the CDW transition. This large change in our devices is due to smaller number of “domains” of CDW involved in the transport compared to bulk crystals.


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