New Materials Will Bring the Next Generation of Quantum Computers

Technologies enabled by quantum science will help researchers better understand the natural world and harness quantum phenomena to benefit society. They will transform health care, transportation, and communications, and enhance resilience to cyber threats and climate catastrophes. For example, quantum magnetic field sensors will enable functional brain imaging; quantum optical communications will permit encrypted communications; and quantum computers will facilitate the discovery of next-generation materials for photovoltaics and medicines. 

Currently, these technologies rely on materials that are expensive and complicated to prepare, and they often require expensive and bulky cryogenic cooling to operate. Such equipment relies on precious commodities such as liquid helium, which is becoming increasingly costly as the global supply dwindles. 2023 will see a revolution in innovations in materials for quantum, which will transform quantum technologies. Alongside reducing environmental demands, these materials will allow for room-temperature operation and energy saving, as well as being low-cost and having simple processing requirements. To optimize their quantum properties, research labs can manipulate chemical structure and molecular packing. The good news is that physicists and engineers have been busy, and 2023 will see these materials moving from science labs to the real world.

Recently, the UK Engineering and Physical Sciences Research Council announced a vision for innovation in materials for quantum technologies, led by Imperial College London and the University of Manchester. The London Centre for Nanotechnology—a collaboration of hundreds of researchers across Imperial, King’s and University College London—has considerable expertise in the simulation and characterization of quantum systems. The UK’s home for measurement—the National Physical Laboratory—just opened the Quantum Metrology Institute, a multimillion-pound facility dedicated to the characterization, validation, and commercialization of quantum technologies. Working together, researchers and industry will usher in a new era in pharmaceuticals, cryptography, and cybersecurity.

Qubits, the building blocks of quantum computers, rely on materials with quantum properties, like electron spin, which can be manipulated. Once we can harness these properties, we can control them using light and magnetic fields, creating quantum phenomena such as entanglement and superposition. Superconducting qubits, the current state-of-the-art for qubit technology, comprise Josephson junctions that operate as superconductors (materials that can conduct electricity with zero resistance) at super-low temperatures (–273ºC). The harsh temperature and high-frequency operation requirements mean that even the most basic aspects of these superconducting qubits—the dielectrics—are tricky to design. At the moment, qubits include materials like silicon nitride and silicon oxide, which have so many defects that the qubits themselves have to be millimeter-sized to store electrical field energy, and crosstalk between adjacent qubits introduces considerable noise. Getting to the millions of qubits required for a practical quantum computer would be impossible with these materials.

2023 will see more innovation in the design of materials for quantum technologies. Of the many awesome candidates considered so far (e.g., diamonds with nitrogen vacancy defects, van der Waals/2D materials, and high-temperature superconductors), I’m most excited about the use of molecular materials. These materials are designed around carbon-based organic semiconductors, which are an established class of materials for the scalable manufacture of consumer electronics (having revolutionized the multibillion-dollar OLED display industry). We can use chemistry to control their optical and electronic properties, and the infrastructure surrounding their development relies on established expertise.

For example, chiral molecular materials—molecules that exist as a pair of non-superimposable mirror images—will revolutionize quantum technologies. Thin, single-handed layers of these remarkably versatile molecules can be used to control the spin of electrons at room temperature. At the same time, the long spin coherence times and good thermal and chemical stability of metal phthalocyanines will see them being used to carry quantum information.

While 2023 will undoubtedly see more bombastic headlines about the operating speeds of quantum computers, materials scientists will be studying, discovering, and designing the next-generation of low-cost, high-efficiency, and sustainable quantum technologies.