Researchers visualized flat band structures associated with exotic electronic phases in stacked graphene layers offset from each other by a “magic angle.” The work corroborates theoretical predictions and has significant implications for phenomena of technological and fundamental interest, such as topological phases and superconductivity. Read more »
ALS Work Using ARPES
Angle-resolved photoemission spectroscopy (ARPES) is a technique in which a highly focused beam of x-rays is used to kick electrons out of the sample. By analyzing the ejected electrons' direction and energy, the researchers can obtain the material's band structure—a map of the electrons' behavior in the material.
Scientists Dive Deep Into Hidden World of Quantum States
Researchers discovered two unique electronic properties—a Van Hove singularity and Fermi surface topology—at the interface between atomically thin oxide materials. The results suggest that the system is an ideal platform for investigating how to control superconductivity at the atomic scale in 2D materials. Read more »
A Scalable Platform for Two-Dimensional Metals
Using a new method for stabilizing a two-dimensional (2D) metal on a large-area platform, researchers probed the origins of the material’s superconductivity. The work represents a notable milestone in advancing 2D materials toward broad applications in topological computing, advanced optics, and molecular sensing. Read more »
A Forked Path for Superconductivity
Uranium ditelluride (UTe2) exhibits a form of superconductivity that could, in theory, enable fault-tolerant quantum computing. Angle-resolved photoemission spectroscopy revealed several aspects of the material’s unusual electronic environment, including one-dimensional conducting channels that are orthogonally oriented. Read more »
Elusive Kagome Electronic Structures Revealed
Electronic-structure studies showed that both infinitely light and infinitely massive particles coexist in a material with a star-shaped (kagome) crystal lattice. The material’s rich array of electronic behaviors shows promise for future spintronic applications and represents a new frontier for studying exotic phases of matter. Read more » 
Chiral Crystals Give Rise to Topological Conductors
Researchers have discovered materials whose chiral crystal structures produce chirality in their electronic behavior. These topological conductors retain their unique electronic properties regardless of defects and open new possibilities in materials research. Read more »
The Best Topological Conductor Yet: Spiraling Crystal Is the Key to Exotic Discovery
Researchers have discovered the strongest topological conductor yet, in the form of thin crystal samples that have a spiral-staircase structure. The realization of so-called topological materials—which exhibit exotic, defect-resistant properties and are expected to have applications in electronics, optics, quantum computing, and other fields—has opened up a new realm in materials discovery. Read more »
A Nanoscale View of Defect Effects on Band Structure
In the first comprehensive study at the ALS involving nanoARPES, researchers probed the electronic effects of defects in monolayer tungsten disulfide at the nanoscale. The extremely small scale of the measurements makes nanoARPES a great discovery tool that will be particularly useful for understanding new materials as they are invented. Read more »
Scientists Take a Deep Dive Into the Imperfect World of 2D Materials
Researchers combined a toolbox of techniques to home in on natural, nanoscale defects formed in the manufacture of monolayer WS2, measuring their electronic effects in detail not possible before. The latest result marks the first comprehensive study at the ALS involving nanoARPES, which researchers enlisted to probe the 2D samples with x-rays. Read more »
Spin-Momentum Locking in Cuprate High-Temperature Superconductors
A form of spin-momentum locking, similar to the strong linkage between electron spin and momentum in topological insulators, has been found in a cuprate superconductor. The results open a new chapter in the mystery of high-temperature superconductors, suggesting that new, unexplored interactions and mechanisms might be at play. Read more »