The Quantum computing concept, initially proposed in the 80’, predicted a gigantic improvement in computation capabilities as compared to its classical counterpart. The possibility to encode information as the superposition of two quantum states, would allow us to tackle complex problems at once in a much shorter time. The potential applications are wide, ranging from medicine and drugs development to materials, artificial intelligence, cryptography and climate prediction among others. However, today’s quantum technologies are suffering from a very high error rate due to decoherence (i.e. loss of quantum information) in their qubits fabricated with superconductors junctions or semiconductors quantum dots. For instance, superconducting and semiconducting qubit devices suffer from an error rate of ~1% versus 10E-22 % for classical computing with only few coupled qubits. Today’s strategy to overcome the too high error rate problem is mainly to increase the density of these qubits above 10E6 per chip and make use of quantum error correction algorithms to build an “error free” quantum computer (i.e. 1 logical qubit = ~ 20 000 “faulty” physical qubits). Given the exceedingly large qubit overhead, quantum computing experiences severe challenges to outperform current classical computers.
Obviously, the real breakthrough for quantum computing is to develop fault-tolerant qubits rather than to focus on upscaling the physical qubit density only. The goal of this proposal is to research radically new materials and architectures to build a “fault-tolerant” qubit device on Silicon substrate (i.e. scalable), that will be immune to decoherence problems. In NOTICE, we will design and synthetize novel crystalline perovskite materials, monolithically integrated on a Silicon substrate, with topological insulating properties to enable the generation of Majorana fermions at the heterointerface with a superconductor. The generated Majorana fermions will hold the quantum information in such “Majorana qubit” which will be resistant to noises and fluctuations due to the topology effect if stable and robust materials presenting the desired properties can be obtained.
Bismuth-based perovskites were down-selected as topological insulator (BaBi(O,F)3) and superconductor ((Ba,K)BiO3) oxides due to the very strong Spin Orbit Coupling present in Bi which will favorize the efficient generation of Majorana fermions at the perfect (pristine) BaBi(O,F)3/(Ba,K)BiO3 heterointerface. With Molecular Beam Epitaxy growth approach together with advanced characterization techniques such as Angle-Resolved PhotoEmission Spectroscopy measurements and ab-initio simulations on the topological insulating properties of the perovskites, we aim to generate a stable topological interface leading to the efficient generation of Majorana fermions. This breakthrough will enable us to fabricate chiral Majorana devices on a Silicon technology platform, providing both reliability and manufacturing scalability.
NOTICE results will pave the way to “fault-tolerant” qubit, bringing a paradigm shift in quantum computing by reducing drastically the gap between logical and physical qubits and the need for quantum error correction algorithms.
