Scientists engineer ultra-thin superconducting ink for quantum computers

It’s made through chemical exfoliation.

Loukia Papadopoulos
Scientists engineer ultra-thin superconducting ink for quantum computers
Representational image of quatnum computing.

Bartlomiej Wroblewski/iStock 

Researchers from Princeton University, Rutgers University, and the University of Regensburg have engineered a chemical exfoliation technique to produce single-molecule-thick tungsten disulfide ink that could be used in quantum computing.

This is according to a report by Phys.org published last week.

“Chemical exfoliation offers another route toward monolayers, with the advantage that it accesses large quantities, which can then be processed into printable inks, moving studies from the laboratory setting to potential industrial applications, especially if the synthesized ink is stable in air,” stated the authors in their paper.

“It is well established that metallic WS2 monolayer nanosheets can be synthesized via Li intercalation of 2H-WS2 and subsequent sonication in water, but these nanosheets are never purely of the 1T′ phase and usually have many defects. While this metallic WS2 has been studied extensively for catalytic applications, to the best of our knowledge, its superconductivity has never been investigated.”

The new method will allow researchers to print very cold circuits inside quantum computers using superconducting ink.

The new material consists of layers of tungsten disulfide and potassium that has been dunked into a sulfuric acid solution in order to be exfoliated. This dissolved the potassium and left behind single-molecule layers of tungsten disulfide that were then rinsed in acid. 

The end result is layers of tungsten disulfide that could be used as a form of ink that could be printed onto various types of surfaces, such as plastic, silicon, or glass, as a one-molecule-thick coating.

Their solution was quite stable, holding up at room temperature without the need for a protective coating for 30 days. Furthermore, cooling it to 7.3K made the coating superconductive. 

The researchers now claim that their new ink could be used in quantum computers or MRI machines where parts would already be cooled to the appropriate temperatures, according to Phys.org.

“In conclusion, we successfully synthesized monolayers of the 2D TI candidate 1T′-WS2 and prepared an air-stable aqueous superconducting ink consisting primarily of 1T′-WS2 monolayers. A printed 1T′-WS2 film is metallic at room temperature and superconducting below 7.3 K with a maximal critical current of 44 mA at 2 K.

The upper critical magnetic field is 30.1 T if the field is applied in plane and 5.3 T in the perpendicular field direction, pointing to unconventional superconductivity,” noted the authors in their paper.

The paper is published in the journal Science Advances.

Study abstract:

Liquid-phase chemical exfoliation can achieve industry-scale production of two-dimensional (2D) materials for a wide range of applications. However, many 2D materials with potential applications in quantum technologies often fail to leave the laboratory setting because of their air sensitivity and depreciation of physical performance after chemical processing. We report a simple chemical exfoliation method to create a stable, aqueous, surfactant-free, superconducting ink containing phase-pure 1T′-WS2 monolayers that are isostructural to the air-sensitive topological insulator 1T′-WTe2. The printed film is metallic at room temperature and superconducting below 7.3 kelvin, shows strong anisotropic unconventional superconducting behavior with an in-plane and out-of-plane upper critical magnetic field of 30.1 and 5.3 tesla, and is stable at ambient conditions for at least 30 days. Our results show that chemical processing can make nontrivial 2D materials that were formerly only studied in laboratories commercially accessible.