Ultrahigh-quality graphene resonators by liquid-based strain-engineering.

Two-dimensional (2D) material-based nanoelectromechanical (NEM) resonators are expected to be enabling components in hybrid qubits that couple mechanical and electromagnetic degrees of freedom. However, challenges in their sensitivity and coherence time have to be overcome to realize such mechanohybrid quantum systems. We here demonstrate the potential of strain engineering to realize 2D material-based resonators with unprecedented performance.

Abrikosov vortex corrections to effective magnetic field enhancement in epitaxial graphene.

Here, we report the effects of enhanced magnetic fields resulting from type-II superconducting NbTiN slabs adjacent to narrow Hall bar devices fabricated from epitaxial graphene. Observed changes in the magnetoresistances were found to have minimal contributions from device inhomogeneities, magnet hysteresis, electron density variations along the devices, and transient phenomena. We hypothesize that Abrikosov vortices, present in type-II superconductors, contribute to these observations.

Graphene quantum Hall effect parallel resistance arrays.

As first recognized in 2010, epitaxial graphene on SiC(0001) provides a platform for quantized Hall resistance (QHR) metrology unmatched by other two-dimensional structures and materials. Here we report graphene parallel QHR arrays, with metrologically precise quantization near 1000 Ω. These arrays have tunable carrier densities, due to uniform epitaxial growth and chemical functionalization, allowing quantization at the robust = 2 filling factor in array devices at relative precision better than 10.

Onsager-Casimir frustration from resistance anisotropy in graphene quantum Hall devices.

We report on nonreciprocity observations in several configurations of graphene-based quantum Hall devices. Two distinct measurement configurations were adopted to verify the universality of the observations (i.e.