One of the most troublesome roadblocks to practical quantum computers is undesirable coupling of qubits to noisy external environment which perturbs the fragile quantum states involved in information retention and processing. Topological superconductivity supporting so called protected boundary states and quasi-particles with non-Abelian statistics such as Majorana fermions may be the solution. InSb quantum wells (QW) are one of the most desirable material systems for the top-down approach in realizing Majorana bound states for topological quantum computing. Because of the lack of suitable semi-insulating substrates lattice-matched to InSb such QWs are typically grown on AlInSb metamorphic buffers deposited on GaAs substrates. However, a high density of pyramid-shaped hillocks forms on such buffers, due to the spiral growth around the screw components of threading dislocations. Their presence may cause undesirable spatial modulation in AlInSb barrier composition as well as variations in InSb QW thickness, increasing electron scattering rates and trapping probability. Suppression of hillocks is thus essential from the perspective of quantum device performance and formation of robust bound Majoranas. After giving a brief overview of the present activities in my research group and introducing the relevant background and I will discuss our quest towards elimination of these features by fine-tuning interactions between atomic steps on the surface.
Zbig Wasilewski is a Professor in the Electrical and Computer Engineering Department at the University of Waterloo. He is internationally renowned for his contributions to the field of Molecular Beam Epitaxy, quantum-dot and quantum-well photonic devices, as well as quantum structures based on high mobility 2D electron gases.
Dr. Wasilewski earned his doctoral degree from the Institute of Physics of the Polish Academy of Sciences in 1986, based on his magneto-optical studies of semiconductors under high hydrostatic pressures. In 1988, after a post-doctoral appointment at the Imperial College, London, he joined the National Research Council of Canada, focusing on molecular beam epitaxial growth and characterization of quantum structures based on III–V semiconductor compounds. In July 2012, Dr. Wasilewski joined the University of Waterloo as a full Professor and Waterloo Institute for Nanotechnology Endowed Chair, where he established the Quantum-Nano Centre MBE Facility (QNC-MBE).
https://uwaterloo.ca/institute-nanotechnology/people-profiles/zbig-wasilewski