Advanced Light Source at Berkeley Lab aids quantum materials research for 30 years

For over 30 years, the Advanced Light Source at Berkeley Lab has assisted scientists worldwide in probing the behavior of quantum materials. Riccardo Comin of MIT and colleagues used data collected at the ALS in 2022 to visualize CsV3Sb5, a kagome material composed of cesium, vanadium, and antimony.

The ALS is undergoing a historic upgrade to generate brighter X-ray beams, which will allow researchers to collect data with greater detail than previously possible and further the boundaries of quantum materials research. Over the years, powerful tools at the ALS have led to advances including early insights into graphene and the discovery of superconducting topological insulators.

Advanced Light Source Enables Kagome Material Quantum State Mapping

Currently, the MAESTRO instrument, part of the Microscopic and Electronic STRucture Observatory at the ALS, plays a crucial role in unraveling the complexities of superconductivity, a quantum property allowing for lossless electrical conduction. This instrument employs Angle-Resolved Photoemission Spectroscopy, or ARPES, which simultaneously maps the energy and momentum of electrons to reveal a material’s electronic band structure; this technique has been pivotal in understanding high-temperature superconductivity and topological insulators.

In 2022, Riccardo Comin, associate professor of physics at the Massachusetts Institute of Technology, and his team leveraged MAESTRO’s ARPES capabilities to identify and measure the velocities of electrons initiating superconductivity within a Kagome metal, a promising quantum material with potential applications in new superconductors and quantum computing approaches. Comin emphasized the importance of MAESTRO in studying quantum materials, stating it provides a snapshot of electron energy spectra. The planned ALS Upgrade will allow for X-ray beams focused to less than 25 nanometers, a resolution sufficient to reveal nanoscale variations in quantum materials currently invisible to researchers.

This enhancement will be particularly valuable in characterizing defects within qubits, which can lead to decoherence and errors in quantum computing; assessing the impact of these impurities has been challenging due to limited tools capable of directly measuring quantum coherence. Comin added that the ALS Upgrade is a very important undertaking for the U.S. synchrotron research community and a significant development that will enable new experiments impacting quantum materials research and other fields. The facility is also exploring upgrades to achieve resolutions below 10 nanometers.

ARPES Instruments Reveal Superconductivity Mechanisms at MAESTRO

Angle-resolved photoemission spectroscopy (ARPES) at the Advanced Light Source has been instrumental in deciphering the complexities of superconductivity for over three decades, and current investigations utilizing the MAESTRO instrument are refining understanding of emergent quantum materials. This detailed mapping of electron energies and momenta reveals the electronic band structure governing a material’s properties, offering crucial insights into superconductivity and other quantum phenomena. The capabilities of MAESTRO extend beyond simply identifying superconductivity; the instrument’s ability to focus X-ray beams to a 10-micrometer spot allows for measurements on exceptionally small samples or specific material regions.

The upgrade will significantly improve the energy resolution, flux, and stability of spin-resolved ARPES techniques, which characterize the direction of electron spin. Riccardo Comin, associate professor of physics at the Massachusetts Institute of Technology, stated that the ALS Upgrade’s brighter, more coherent light is critical to seeing how a particular defect spoils coherence in a qubit.

ALS Upgrade to Enhance Nanoscale Quantum Material Resolution

This work exemplifies the three decades of contributions the ALS has made to quantum materials research, a period marked by advancements in understanding superconductors, topological insulators, and correlated electron materials. Now, a substantial upgrade to the ALS promises to dramatically enhance its capabilities, allowing scientists to probe these materials with unprecedented detail and resolution. The ALS Upgrade project focuses on generating brighter beams of X-ray light, a critical step in pushing the boundaries of quantum materials investigation.

This improvement will enable data collection with far greater precision than previously possible, resolving nanoscale variations currently invisible to existing instruments. Specifically, the upgraded facility will focus X-ray beams to less than 25 nanometers, a scale sufficient to observe subtle changes within quantum materials. Ming Yi of Rice University utilized these techniques to demonstrate a method for regulating electron spin within crystal compounds, potentially paving the way for next-generation spintronic devices.

Riccardo Comin, associate professor of physics at the Massachusetts Institute of Technology, said that the ALS Upgrade is a very important undertaking for the U.S. The anticipated improvements extend beyond ARPES, impacting coherent soft X-ray scattering, a technique essential for understanding how electrons and their spins are arranged within materials. As electronics approach the limits of silicon-based technology, the ALS Upgrade is poised to accelerate fundamental research into quantum materials with practical applications, transforming how the researchers study these materials.

Spin-Resolved ARPES Advances Next-Generation Spintronics Research

Advancements in spin-resolved angle-resolved photoemission spectroscopy (ARPES) facilitated by the Advanced Light Source (ALS) are reshaping the landscape of next-generation spintronic devices. Researchers are now capable of more precisely manipulating electron spin within crystalline compounds, opening avenues for faster, smaller, and more robust electronics. This control could yield desirable properties for future applications in electronics and spintronics, and also supports a quantum theory predicting superconducting properties that could accelerate quantum computation.

The ALS Upgrade project will significantly enhance the capabilities of spin-resolved ARPES by improving energy resolution, the rate of X-rays impacting a sample, and overall stability. Current techniques utilize 3D detectors to characterize the direction of electron spin, but the upgraded facility will allow probing of electron coherence at smaller length scales previously inaccessible.

Defects within qubits can disrupt quantum phase relationships, leading to processing errors. The upgraded facility’s brighter, more coherent light will enable researchers to visualize how specific defects disrupt this delicate state, and to shape material properties for improved qubit performance.

Developed by Sophie Morley and Sujoy Roy, this microscope will extend analysis to a broader range of materials, including both thin 2D materials and thicker single crystals. Morley explains that the brain is an instrument that can do remarkable computation with very little energy, and neuromorphic computing is interested in how we can harness electronic properties in materials to replicate aspects of the brain’s neural system, relying heavily on the advanced capabilities the ALS Upgrade will provide.

More like this

Quantum FeaturesBerkeley Lab Advances Quantum Computing Tech

Artificial IntelligenceAI Accelerates Discovery at Berkeley Lab

Quantum Research NewsQSA Trains 150+ Quantum Students Annually at Berkeley Lab

Quantum Research NewsBerkeley Lab’s quantum light source aids neuromorphic computing