Periodic Reporting for period 3 - NOTICE (Novel Oxides and Topological Interfaces for quantum Computing Electronics)
Berichtszeitraum: 2023-09-01 bis 2025-02-28
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.
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.
- Ab initio calculations of Topological Insulators Perovskites:
In this research activity we investigated the different Bi-based candidates which could potentially present topological insulating properties.
- Installation of new HW on the MBE setup
In the framework of the ERC novel HW was installed on existing setup in order to enable UHV transfer of MBE grown samples to the ARPES characterization tool.
- BaBiO3 perovskite epitaxy
The main research activity is currently focusing on the synthesis and crystal growth of the topological insulating perovskite BaBiO3. This is done via molecular beam epitaxy technique on various substrates, including silicon. Physical characterizations (TEM, XRD, AFM, ...) are largely used to assess the perovskite material quality.
- Transport characterization of TIs
The more recent initiated research activity on the development of a platform to demonstrate topological carrier transport via gated hall bars.
In this research activity we investigated the different Bi-based candidates which could potentially present topological insulating properties.
- Installation of new HW on the MBE setup
In the framework of the ERC novel HW was installed on existing setup in order to enable UHV transfer of MBE grown samples to the ARPES characterization tool.
- BaBiO3 perovskite epitaxy
The main research activity is currently focusing on the synthesis and crystal growth of the topological insulating perovskite BaBiO3. This is done via molecular beam epitaxy technique on various substrates, including silicon. Physical characterizations (TEM, XRD, AFM, ...) are largely used to assess the perovskite material quality.
- Transport characterization of TIs
The more recent initiated research activity on the development of a platform to demonstrate topological carrier transport via gated hall bars.
It is the target of the project to present a device that enables novel generation of quantum computers based on fault tolerant qubit devices. This requires developments on materials, material processing and device processing as well as a deep understanding and control of the physical properties of that device system.
The BaBiO3 epitaxy control is a crucial step for the follow up of the project. The understanding of the crystal phases and the link with the ab-initio calculations brings unprecedent understanding on this novel material.
The BaBiO3 epitaxy control is a crucial step for the follow up of the project. The understanding of the crystal phases and the link with the ab-initio calculations brings unprecedent understanding on this novel material.