The broad theme of our laboratory is the search and/or study of quantum matter on-a-chip. Material-wise, we use extremely low-disorder GaAs/AlGaAs grown in some of the best Molecular Beam Epitaxy (MBE) facilities in the World, as well as the cleanest material in Nature, liquid 3He near T=0. We carry out measurements down to ~8 mK, in high magnetic fields up to 16T. In our laboratory, we develop and implement novel tools and techniques such as resistively detected NMR with 'too few spins’, all-electrical thermodynamic measurements, refrigeration on-a-chip, and spectrometer-based mass counting for nanofluidics at low temperatures. Starting from raw semiconducting material, we tailor-fabricate structures for electrons, or nanoholes for quantum fluids using cutting-edge clean room fabrication processes evolved from the nanotech community. In our laboratory, the search for new quantum phases of matter occurs when the nanotech tools and low-temperature know-how connect with quantum physics.
The Faraday Effect has long explained a linear relationship between perpendicularly applied magnetic field and light traveling through a medium. We have found the quantum version of the Faraday effect in low temperature in the microwave regime. We use high mobility semiconductor wafers to induce quantized phases with modest magnetic fields (<6T). The quantum analog of the classical Faraday effect follows in 1/B in correspondence to the quantum Hall states that are activated in this optical field and [theta_F] quantizes as a function of [alpha], provides a geometric prescription for the fine structure constant.
[Suresh, V., Pinsolle, E., Lupien, C., Martz-Oberlander, T. J., Lilly, M. P., Reno, J. L., Gervais, G., Szkopek, T., Reulet, B. Phys. Rev. B. 102, 085302 (2020)]
Search for spin-polarized Non-abelions
In the ground state of extremely clean (low-disorder) GaAs/AlGaAs interface, typically ~30 nm wide, are predicted particles with quantum statistics that, upon their exchange, do not result in a simple +/- sign in their wavefunctions, such as well-known for bosons or fermions, but rather involved non-abelian (non-trivial!) phases. These so-called non-abelions have been shown to underlie a paradigm for fault-tolerant (topological) quantum computations. In our laboratory, experiments are conducted in an effort to confirm or invalidate whether or not such quantum statistics are truly realized in Nature.
[K. Bennaceur, C. Lupien, B. Reulet, G. Gervais, L. N. Pfeiffer and K. W. West, Phys. Rev. Lett. (2018)]
2D Atomic Crystals and Bandgap Engineering (with Prof. Szkopek)
In collaboration with Prof. Szkopek from McGill engineering we fabricate ultra-thin (∼5-50 nm) field-effect transistors made out of various allotropes exfoliated or grown in ultra-high vacuum. In particular, we are pushing towards in the single-atomic layer limit of ‘post-graphene’ materials. Fundamental questions regarding 2D materials and applied questions on bandgap engineering are being explored in parallel.
[V. Tayari, B.V. Senkovskiy, D. Rybkovskiy, N. Ehlen, A. Fedorov, C.-Y. Chen, J. Avila, M. Asensio, A. Perucchi, P. di Pietro, L. Yashina, I. Fakih, N. Hemsworth, M. Petrescu, G. Gervais, A. Gruneis, and T. Szkopek, Phys. Rev. B. (2018)]
1D-1D Coulomb drag in quantum wires (collaborative work at Sandia Nat Labs, USA).
We are also collaborating with the Sandia group led by Dr. Mike Lilly, and are interested in students who would work with this group at Sandia on projects involving the fabrication and study of vertically-coupled one-dimensional quantum wires, separated by less than 10 nm. Please contact us if you want to hear more about this exciting possibility.
[D. Laroche, G. Gervais, M.P. Lilly and J.L. Reno, Science (2014)]
Semiconductors in high-magnetic fields
Using the highest continuous DC magnetic field in the World, in Tallahassee, Florida, we are performing experiments on extremely quality semiconductor heterojunction in an effort to study electron correlations under magnetic fields as high as 45T.
[V. Tayari, N. Hemsworth, I. Fakih, A. Favron, E. Gaufrès, G. Gervais, R. Martel and T. Szkopek, Nature Commun. (2015)]
Classical and Quantum nanofluidics
We haven't completely forgotten about the quantum correlations existing in quantum materials such as 3He and 4He. We are interested in performing measurements with classical gases and liquids when confined over an extremely small scale, ~nm. In tailor-fabricated nanoholes semiconductor membranes, we are measuring the conductance of very small holes, down to a a few nm, in an attempt to understand gas dynamics at the nanoscale. We also want to perform flow measurement of quantum fluids very near T=0 in an effort create new state of quantum matter. Wanna know some more, call us up!
[P-F Duc, M.Savard, M. Petrescu, B. Rosenow, A. Del Maestro, and G. Gervais, Science Advances 1, (2015).]
Black Hole on a Chip
That's right... [work in progress]
Ultra Low Temperature Scanning Probe Microscope
In a group effort consisting of five faculty, one Post-Doc, and a PhD student, all from McGill, we are in the process of constructing an atomic force microscope (AFM) that will operate in a ~50 mK environment with a 16 Tesla magnet. This experimental tour de force will be (we hope) a World first for imaging exotic nanoscale systems. The 50 mK environment will be created using a dilution refrigerator inserted into a superconducting magnet. The AFM is currently working well at Liquid Helium temperatures in High Magnetic Fields (> 15 Tesla!).