Grant: Canada Research Chairs

Quantum computing is expected to revolutionize our society with key progress being made towards commercial applications in areas such as cybersecurity, pharmaceuticals, materials, banking, and finance. However, significant scientific and engineering challenges persist including the pervasive decoherence error caused by vibrations, temperature fluctuations, and other interactions with the outside environment. This leads to “noise”, and ultimately destroys the exotic quantum properties. One approach to address decoherence is to use the braiding of a novel kind of particle, so-called Majorana fermions, found at the vortex core of topological superconductors. Due to their topological nature, the encoded quantum information is protected against environmental effects. Yet, to date, the use of topological superconductors, the material platform used to create Majorana fermions, has been limited to very low temperatures. Guided by theoretical predictions, we will explore high-temperature topological superconductivity emerging in twisted structures of cuprates, the archetypical and most celebrated family of high-temperature superconductors. Recently, a twisted bilayer of cuprates has been predicted to exhibit topological superconductivity at a temperature as high as the original pristine material. In this program, we will fabricate high-quality twisted cuprate structures using an in-situ exfoliation and stacking method in ultra-dry environments. We will study their superconducting order parameter using advanced optical tools, such as transient reflectivity and polarization-resolved Raman spectroscopy. Finally, by optical polar Kerr effect, we will probe the breaking of time-reversal symmetry at the twisted interface: the fingerprint of topological superconductivity. Our goal is to systematically study the emerging physics in the vortex, as well as around defects and edge boundaries, of this most promising platform for Majorana fermion. If successful, our work will provide the first material example of high-temperature superconductivity with nontrivial topology, laying the foundation for future quantum technologies. The proposed research program not only presents a path towards high-temperature topological superconductivity, it will also provide unprecedented insights into the physics and applications of quantum materials, and help us understand emergent phenomena, while advancing UBC and Canada to the very forefront of this exciting and rapidly growing field.