Department of Physics

Abstract: With the announcement of quantum supremacy by Google in 2019, we entered a new era in computing.  While Google’s Sycamore quantum processor demonstrated exponentially superior performance over the most advanced classical supercomputer for a specific task, quantum advantage and real-world application is still over the horizon due to quantum decoherence and errors at the qubit level.  Topological qubits are theoretically more robust than the superconducting qubits used in Sycamore, but material inhomogeneities hinder investigations of the elusive Majorana modes needed for topological quantum computations.  New material platforms are needed for reliable quantum computations using topological materials.  The interface between two-dimensional topological Dirac states and an s-wave superconductor is expected to become a topological superconductor and support Majorana bound states.  Realizing these novel states of matter and their applications requires simultaneous control over superconductivity and spin-momentum locked topological interface states.  Here I will discuss our efforts to create new topological superconducting platforms with enhanced properties and reduced disorder.  I will discuss new material platforms as FeTe_1-xSe_x grown on Bi₂Te₃ where reduced Se doping not only reduces disorder from chemical inhomogeneities but enhances spin-momentum locking of the topological interfacial states while maintaining a superconducting T_c > 10 K.  I will also outline a new templated synthesis approach for creating novel proximitized materials as well as new nonlocal transport methods for more reliable Majorana mode interrogation.  These co-designed efforts enable new pathways for scientific discovery and development of quantum computing and sensing applications.