Electromechanical properties of suspended graphene

• Applicant: Professor Dr. Felix von Oppen, since 4/2016
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 2010 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 172371789

In the recent years, graphene has positioned itself as one of the outstanding candidates, together with carbon nanotubes, for the materia prima of high-performance nanoelectromechanical devices. This is due to its high flexibility, resistance to deformations or rupture and low mass, together with high electronic mobilities and the possibility of controlling its transport properties by either appropriately gating the device or via strain. Moreover, the peculiar nature of the carriers, being Dirac fermions, brings new physics with it. Suspended graphene allows for extra clean samples that show new Quantum Hall effects to an unprecedented level of detail. Even more exciting yet, experiments are pushing the limits to observe macroscopic quantum phenomena in these systems. It is the aim of this proposal to continue with our work on the interplay between electronic transport and vibrational degrees of freedom in graphene and graphene related structures, with emphasis on non-equilibrium phenomena. In the previous period of funding we have made advances on the understanding on how phonons affect the temperature dependence of the resistivity both of monolayer and bilayers graphene. As a first step towards a theory of graphene resonators, we have also developed a powerful scattering matrix formalism for nanoelectromechanical systems. For the coming funding period, we propose to apply this general framework to graphene resonators in various regimes. Motivated by recent experiments, we specifically propose to study the quantum Hall regime, focusing both on mechanical detection of quantum Hall states and the modification of quantum Hall states by mechanical vibrations. Finally, we plan to address graphene resonators in the quantum regime as well as a particularly intriguing class of optical phonon modes (Kekule mode).

• DFG Programme: Priority Programmes
• Subproject of: SPP 1459: Graphen
• Ehemalige Antragstellerin: Professorin Dr. Silvia Viola Kusminskiy, until 3/2016