superconductors – Lightsources.org

How the Advanced Light Source Is Accelerating Our Quantum Future

2026/08/262026/09/17

Key Takeaways

Quantum materials are key to advancing next-generation electronics, information technologies, and quantum computers.
For over 30 years, world-leading X-ray tools and experts at the ALS have helped researchers from all over the world investigate quantum materials such as superconductors, topological insulators, and correlated electron materials.
The Advanced Light Source Upgrade project will generate brighter beams of X-ray light, allowing researchers to push the boundaries of quantum materials research further by collecting data with far greater detail than has been possible before.

For more than three decades, the Advanced Light Source (ALS), a DOE Office of Science user facility at Lawrence Berkeley National Laboratory (Berkeley Lab), has helped scientists from all over the world advance their understanding of quantum materials — solids whose electrons interact so strongly with each other that entirely new collective behaviors such as superconductivity, exotic magnetism, and other phenomena emerge, defying the predictions of conventional theory.

The ALS is a leading third-generation synchrotron light source that specializes in soft X-ray and UV light instrumentation while providing researchers access to a full spectrum of X-ray light for scientific research. Through the years, powerful tools at the ALS have helped researchers from academia, the national labs, and industry identify and confirm the presence of quantum phenomena, leading to a number of significant advances, including early insights into graphene; the discovery of superconducting topological insulators; the development of a one-atom-thin magnet that could advance next-generation memory devices; new insight into the magnetic properties enabling read/write memory and memory storage devices; and a method for building qubits for quantum computers from 2D metal organic frameworks (MOFs).

Read more on the ALS website

Image: UC San Diego doctoral researchers Wei “Francis” He (far left), Kate Matthews (second from right), and Robin Glefke (far right) from the Alex Frañó group at the COSMIC Beamline (7.0.1) at the Advanced Light Source. They are working with ALS staff scientists Sujoy Roy (center) and Sophie Morley (second from left) to investigate the properties of a quantum material of interest for a neuromorphic system.

Credit: Robinson Kuntz/Berkeley Lab

Cu2Ge: A New 2D Topological Semimetal

2025/01/292025/01/30

Members of the “Spectroscopy of Novel Quantum States” team from the Paris Institute of Nanosciences, Sorbonne University, came to the URANOS beamline (synchrotron Solaris) to study the electronic properties of a recently synthetized material: Cu₂Ge which is a so-called “nodal line” topological semi-metal. More generally, their scientific objectives are focused on understanding the electronic and magnetic properties of low-dimensional systems such as superconductors, topological and magnetic materials, or Mott insulators.

Among various metal/semiconductor systems, copper/germanium alloys have been studied since the 1990s to understand the formation mechanisms of Schottky barriers, fundamental to diodes of the same name. This Cu₂Ge system has attracted renewed interest due to recent predictions of density functional theory (DFT) calculations. Indeed, these calculations predict that the 2D alloy Cu₂Ge has a band structure with a 1D intersection of valence and conduction bands, characteristic of a topological semimetal with a Dirac nodal line. In this work, we have experimentally demonstrated for the first time that it is possible to synthesize Cu₂Ge on a surface of a copper crystal and that its electronic structure exhibits the expected characteristics of the purely 2D case. Its properties make this alloy a promising candidate for high-frequency electronic applications and an ideal system for studying exotic properties that can emerge in nodal line materials.
Two-dimensional materials are widely studied for their exceptional properties, which allow for potential applications in various fields such as photovoltaics, catalysis, microelectronics, and biomedicine. Additionally, some of these 2D systems exhibit topological properties, further increasing the possibility of discovering new electronic behaviors without a bulk equivalent. Such is the case for Cu₂Ge, an alloy consisting of an atomic plane of copper and germanium. Although Cu/Ge alloys were studied several decades ago for Schottky barrier formation, more recent DFT calculations shed new light on these systems. They reveal that, in the case of a 2D Cu₂Ge layer, the band structure should exhibit cones intersecting along two closed loops. These “loops” are known as Dirac lines. When these lines are close to the Fermi level, the material noteworthy properties: the potential for higher carrier densities than graphene while maintaining very high carrier velocity.

Unveiling finer details in the physics of materials

2023/02/212023/03/28

Scientists at the European XFEL’s SCS instrument routinely use a technique called transient X-ray absorption spectroscopy (XAS) to investigate materials that have applications in data storage and processing, catalysis, or in the search for room temperature superconductors. Investigating very small changes in the motion of electrons within a material’s structure on ultrashort timescales provides scientists with fingerprints of the complex processes at play within them. This helps them characterise samples that are important for energy and materials research.

Using the European XFEL’s brilliant pulses, researchers can overcome some of the issues of conventional transient XAS—such as long measurement times—but the varying intensity of European XFEL’s pulses provides its own challenges. Now, scientists at SCS have implemented a new sampling scheme for improving the efficiency of such measurements.

Read more on the European XFEL website

Image: The X-ray beam is split into three copies. Two of these copies are passed through identical samples of the material under investigation, with one of these samples also being illuminated by a laser (‘optical laser’ in the figure). This transforms it into a new state, interesting to researchers. From this, scientists are able to ‘subtract’ detrimental noise, revealing the finest details of the sample under investigation.