Quantum computer rendering
Shutterstock / Bartlomiej K. Wroblewski Source: Shutterstock
Superconducting inks that can be printed on surfaces in single-molecule-thick layers could help build circuits for quantum computers. Tungsten disulfide ink is more stable than other superconducting inks, easier to manufacture, and suitable for future applications.
If a material is superconducting, electricity can pass through it with zero resistance, so energy can be transferred very efficiently. Superconducting materials also have special magnetic properties, but they tend to be difficult to make and break down when exposed to air or temperatures far from absolute zero.
Xiaoyu Song and Leslie Schoop Princeton University and colleagues produced tungsten disulfide ink using a process called chemical exfoliation. They started with a material made of alternating layers of tungsten disulfide and potassium. “Imagine a crepe cake. All these crepes on top of each other, and in between there’s a cream he filling. Tungsten disulfide is the crepe and potassium is the filling,” Song says. When the layered material is placed in dilute sulfuric acid, the potassium dissolves, leaving only a thin layer of tungsten disulfide, much like soaking a crepe cake in water.
After washing away the acid and potassium residues, the researchers were left with a thin layer of tungsten suspended in water. can form a layer of tungsten disulfide.
The printed patterns remained stable for at least 30 days at ambient conditions without any protective container or coating. Freezing to temperatures below 7.3 Kelvin (-266°C) made the ink superconductive even after being left outdoors for some time. “You can take it with you, or you can set it up at room temperature, and then you just freeze it,” he says. “But you need liquid helium. Unfortunately, I couldn’t do it in my freezer at home.”
This process is much simpler than those that have been used for other superconducting inks, which required a protective layer to prevent degradation over time. This may facilitate industrial production of this ink, but its temperature requirements hinder some potential applications. “It might still be practical with something that is already cooled, like a quantum computer or his MRI machine, which cools the system significantly,” he says. In the future, researchers hope to be able to use this method to create inks that are superconducting at high temperatures.
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