Scientists from the Penn State Center for Nanoscale Science (CNS) have made a breakthrough in quantum computing that could revolutionize the field. In a paper published in Nature Materials, the team revealed that a new form of heterostructure, made up of layered two-dimensional (2D) materials, may hold the key to overcoming some of the major barriers to quantum computing's wider application.

Unlike regular computers, quantum computers are based on quantum mechanics and operate using qubits, which can represent both a "0" and a "1" at the same time, thanks to a phenomenon known as superposition. However, the performance of these qubits can be easily disrupted by the surrounding environment, leading to errors in computing.

The solution to this problem could be a topological qubit, which is a theoretical type of qubit that could potentially be immune to these types of errors. The key lies in developing materials that can protect the quantum state from the environment.

The researchers at CNS developed a special type of heterostructure made up of a layer of topological insulator material, bismuth antimony telluride or (Bi,Sb)2Te3, and a layer of superconducting material, gallium. The heterostructure is challenging to create, as different materials have different lattice structures, and may react chemically when combined. However, the researchers used a synthesis technique called confinement heteroepitaxy, which involved inserting a layer of epitaxial graphene between the gallium layer and the (Bi,Sb)2Te3 layer. This technique allowed the layers to combine seamlessly without reacting with one another chemically.

The team demonstrated that the technique is scalable at the wafer level, which could make it a viable option for future quantum computing. A wafer is a round slice of semiconductor material that serves as a substrate for microelectronics. The heterostructure has all the elements of a topological superconductor and could potentially be used to build a topological quantum computer.

The researchers acknowledge that there is still much work to be done, but they believe they have taken an important step towards realizing a topological superconductor. "The material is key so our collaborators are trying to improve the material," said Cequn Li, graduate student in physics and first author of the study. "This means better uniformity and higher quality. And our group is trying to make more advanced devices on these kind of heterostructures to probe the signatures of topological."

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