Magnesium Coating Enhances Tantalum’s Quantum Computing Properties: A Breakthrough at Brookhaven National Laboratory

Unlocking the Power of Quantum Computing with Tantalum

Teams of scientists at the U.S. Department of Energy's Brookhaven National Laboratory have made a significant breakthrough in the field of quantum computing. Their research reveals that adding a layer of magnesium improves the properties of tantalum, a superconducting material that holds immense promise for building the foundation of quantum computers - qubits.

Tantalum, when used in its purest form, offers optimal performance in quantum computing. However, the metal oxidizes easily, which can affect its purity and in turn, the temperature at which it operates as a superconductor. To overcome this challenge, the scientists experimented by adding a layer of magnesium to the tantalum, resulting in a promising solution.

Magnesium - The Game-Changer

By coating tantalum with a thin layer of magnesium, the scientists managed to block the oxidation of tantalum. The magnesium layer sponges out impurities, resulting in purer tantalum with a higher superconducting transition temperature. This discovery could potentially boost tantalum's ability to retain quantum information in qubits and could pave the way for high-performance quantum computing systems.

The team utilized advanced tools to make tantalum thin films, both with and without a protective magnesium layer. The purpose was to determine whether the magnesium coating would effectively minimize tantalum oxidation. The results were positive, confirming the success of the magnesium coating in protecting the tantalum.

Deeper Insight into Tantalum Oxide

Researchers from Brookhaven National Laboratory and Pacific Northwest National Laboratory collaborated on a study of tantalum oxide, which forms on the surface of tantalum and can hinder the material's ability to retain quantum information. Using a combination of scanning transmission electron microscopy (STEM) and computational modeling, they were able to directly measure the atomic structures and bonding states of the oxide layer and tantalum film.

The team discovered that the interface consists of a suboxide layer nestled between the periodically ordered tantalum atoms and the fully disordered amorphous tantalum oxide. Also, they found that the fully oxidized amorphous layer acts as an insulator, while the suboxide layer retains features of a metal. This presence of both fully oxidized tantalum and a suboxide layer could potentially be responsible for the loss of coherence in qubits made of this superconducting material.

Future Implications

This breakthrough is a part of the Co-design Center for Quantum Advantage (C2QA) and made use of the facilities at Brookhaven, including the Center for Functional Nanomaterials, the National Synchrotron Light Source II, and the Condensed Matter Physics & Materials Science Department. The research also utilized computational resources at the National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory.

These findings provide valuable insights and new materials design principles for the advancement of quantum computing technology. The research not only presents significant strides in quantum computing but also showcases the remarkable potential of materials science in revolutionizing technology.