Quantum Electro-Mechanical Engineering of Nanosystems

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Electro-mechanical interactions are enhanced at the nanoscale, such that the boundary between mechanics and electronics can be blurred. To fully exploit quantum nanotechnology, it is essential to understand and control simultaneously the mechanics (phonons, strain, defects) and electronics (quantum phase, screening, correlations) of nanosystems. We will study this hybridization of electro-mechanics in some of the most promising and tunable nanomaterials: strain-engineered graphene, single-wall carbon nanotubes (SWCNTs) and monolayer MoS2. Our approach is unique as we have developed the methods to fabricate extremely clean and small transistors (< 10 - 50 nm) suited for strain-engineering. We will strain these devices up to 10%, while measuring their electronic spectrum at low T and under high magnetic fields. We will explore high-impact fundamental and applied science: (1) Strain transistors, valleytronics and strain-Quantum Hall Effect, (2) Strain engineering of the thermal conductivity and thermopower, (3) Ultra-strong electron-vibron coupling in nano-electromechanical systems (NEMS). The high-impact of the proposed work comes from two facts: our samples are roughly an order of magnitude smaller than most ultra-clean graphene/ SWCNT/ MoS2 suspended devices studied by other groups (stronger electro-mechanical coupling), and we will map out their electronic and thermal transport while controlling simultaneously their strain and electromagnetic environment. This unique exploration will allow us to make quantitative tests of the e-v couplings in NEMS, and strain engineering of electronic and thermal transport. For instance, using a uniaxial strain in ballistic graphene we aim to create mechanically controlled quantum transistors. Similarly, we expect to be able to control the thermal conductivity of graphene and the thermopower of molybdenum-disulfide using strain. We will also use strain to increase the frequency of nano-oscillators (NEMS) and reduce their energy dissipation. These studies are essential to exploit quantum nanotechnology where mechanics and electronics hybridize. We aim to build several proof-of-principle applied devices: strain-transistors, thermal transistors, ultra-high frequency NEMS and mechanical qubits.