In the heart of Kolkata, India, researchers at the Centre for Quantum Engineering, Research and Education (TCG-CREST) are pushing the boundaries of superconductivity, with potential implications that could revolutionize the energy sector. Led by Snehal Mandal, a team of scientists has developed two superconducting thin film systems that could pave the way for more efficient and powerful quantum technologies.
The research, published in the journal Materials for Quantum Technology, focuses on the development of superconducting qubits, which are the building blocks of quantum computers. These qubits utilize Josephson junctions (JJs), and the optimization of materials is crucial for engineering high-coherence qubits. The team’s work centers around two superconducting thin film systems grown on silicon (Si), with one system derived from the other through a process called annealing.
The first system is a hybrid cobalt (Co) thin film, which exhibits superconductivity at a transition temperature (Tc) of 5 Kelvin. This film is unique because it forms a self-organized hybrid superconductor/ferromagnet/superconductor (S/F/S) structure. “The anisotropy in the upper critical field between the in-plane and out-of-plane directions suggests a quasi-2D nature of superconductivity,” Mandal explains. This quasi-2D nature could be crucial for developing more efficient quantum devices.
The second system is a cobalt disilicide (CoSi2) film, prepared by annealing the Co film. This film shows a superconducting transition temperature of 0.9 Kelvin, which, while lower than the Co film, offers other advantages. Despite containing grain boundaries, the CoSi2 film demonstrated a perpendicular critical field of 15 millitesla and a critical current density of 3.8×10^7 Am^-2, comparable to epitaxial CoSi2 films. These properties are promising for high-coherence qubits, which are essential for stable and reliable quantum computing.
One of the most exciting aspects of this research is the potential for integrating different quantum functionalities on the same substrate. Localized annealing by laser pulses could enable the coexistence of S/F/S and S/I/S junctions, opening up new possibilities for quantum device design. “This could lead to more complex and powerful quantum circuits,” Mandal suggests, “potentially revolutionizing the way we process information and manage energy.”
The implications for the energy sector are significant. Superconducting materials have the potential to transmit electricity with virtually no resistance, leading to more efficient power grids. Moreover, the development of high-coherence qubits could enable more advanced simulations of energy systems, leading to better optimization and management.
The research also highlights the importance of materials optimization in the field of quantum technology. The unique properties of the Co and CoSi2 films, such as their critical current densities and upper critical fields, are a testament to the potential of materials science in driving technological innovation.
As the world continues to grapple with energy challenges, the work of Mandal and her team offers a glimmer of hope. By pushing the boundaries of superconductivity, they are not only advancing the field of quantum technology but also contributing to a more sustainable and efficient energy future. The journey from the lab to the power grid is long, but every breakthrough brings us one step closer. The findings were published in the journal Materials for Quantum Technology, which translates to English as Materials for Quantum Technology.