Jülich Summer Academy

Quantum materials

Complex and sensitive

However, finding suitable quantum materials for these new technologies is anything but easy. The quantum phenomena that give materials their special physical properties are complex, and the underlying quantum states are extremely sensitive.

To complicate matters further, unlike established technologies, the quantum states must be controlled in a very targeted manner if they are to be used to store information, for example. For a limited number of qubits – the computing units of quantum computers – this has already been achieved with semiconductors and superconductors. But in order to realize quantum computers with millions of qubits in the future, either the materials used today must be further optimized or completely different ones must be developed.

Sights set on exotic particles

At Jülich, researchers are investigating and developing quantum materials that reveal their properties under extreme conditions such as ultra-low temperatures or strong magnetic fields. A well-known example for which low temperatures are necessary is the quantum phenomenon of superconductivity. In this case, current flows below a critical temperature without electrical resistance. Another class of materials that are still relatively new are topological insulators. On the surface of these insulators, electrons move depending on their electron spin, while the material in the interior behaves like an electrical insulator.

As an example, Jülich researchers were the first to succeed in integrating a topological insulator into a conventional superconducting qubit. These results are an important step on the way to realizing what are known as Majorana qubits. This type of qubit is regarded as a particularly promising candidate. Made of two quantum materials, these hybrid qubits are considered to be significantly more stable than semiconducting or superconducting qubits, which are sensitive and therefore prone to errors.

Top-class facilities

In their targeted search, Jülich researchers rely on theoretical models and calculations as well as on experimental testing of the materials. To enable this, Jülich offers unique technology laboratories such as the Helmholtz Nano Facility (HNF), where scientists can produce quantum chips, for example. In addition, construction began two years ago on the Helmholtz Quantum Center (HQC), which covers the entire spectrum of quantum computing research – from the exploration of quantum materials to the development of prototypes.

Many other facilities are also available, from supercomputers to neutron sources and special electron microscopes. Jülich researchers are also developing new instruments such as the quantum microscope, a unique scanning tunnelling microscope for investigating quantum effects.

Further information

Press release

Jülich Quantum Researchers Build First Hybrid Quantum Bit Based on Topological Insulators

With their superior properties, topological qubits could help achieve a breakthrough in the development of a quantum computer designed for universal applications. So far, no one has yet succeeded in unambiguously demonstrating a quantum bit, or qubit for short, of this kind in a lab. However, scientists from Forschungszentrum Jülich have now gone some way to making this a reality.

Press release

Quantum Microscope Made in Jülich

Scanning tunnelling microscopes capture images of materials with atomic precision and can be used to manipulate individual molecules or atoms. Researchers have been using the instruments for many years to explore the world of nanoscopic phenomena. A new approach by physicists at Forschungszentrum Jülich is now creating new possibilities for using the devices to study quantum effects.