Researchers found a way to reconstruct quantum geometric tensors (QGTs)—mathematical entities that encode how an electron’s wave function is shaped by its quantum environment. The mapping of QGTs enables the discovery and control of novel quantum phenomena such as superconductivity and unconventional electronic phases. Read more »
Hide-and-Seek with Sneaky Electrons in Solids
Researchers used angle-resolved photoemission spectroscopy (ARPES) at the Advanced Light Source (ALS) to demonstrate the existence of dark—state electrons in solids for the first time, providing insights into complex phenomena in physics, such as high-temperature superconductivity and optoelectronics.
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Big Twist Leads to Tunable Energy Gaps in a Bilayer Stack
Researchers found that twisting 2D layers at atypically large angles opens up potentially useful energy gaps in the material’s band structure. The results suggest a new way to tune materials for optoelectronic applications and provide a platform for exploring novel “moiré” phenomena beyond those observed at small twist angles. Read more »
Flat Bands Signal Electrons Trapped in 3D
Researchers found flat electronic band structures—known hallmarks of electrons trapped in two dimensions—but in a material that extends this phenomenon to three dimensions. The work opens up a material framework for exploring superconductivity and other exotic states in three dimensions for advanced electronic applications. Read more »
Doped Nickelate Enters a New Phase with Spintronics Potential
Rare-earth nickelates are known to undergo a metal-to-insulator phase transition as temperature decreases, the mechanism of which is not well understood. Here, researchers observed a new low-temperature phase that’s both metallic and antiferromagnetic—an unusual combination with potential value in spintronics. Read more »
Charge Density Wave Found in Magnetic Kagome Crystal
Researchers discovered a wave-like charge order in a magnetic material with a “kagome” geometric structure and obtained clues to the order’s origins in the material’s electronic structure. By helping to connect certain structures with emergent quantum properties, the work brings us a step closer to the goal of creating materials by design. Read more »
What Drives Electron–Hole Asymmetry in Graphene?
Using the ALS, researchers determined that interactions between electrons are what give rise to the divergent effects observed when graphene is doped with electrons versus holes. A better understanding of this electron–hole asymmetry could lead to new avenues for generating exotic material phases, including unconventional superconductivity. Read more »
Scientists Discover ‘Secret Sauce’ Behind Exotic Properties of New Quantum Material
Kagome metals have long mystified scientists for their ability to exhibit collective behavior when cooled below room temperature. A research team has discovered that the kagome electrons’ unusual synchronicity is due to another behavior known as an electronic singularity, or the Van Hove singularity, which involves the relationship between the electrons’ energy and velocity. Read more »
The Elusive Electronic Structure of Liquid Metals Unveiled
Over 50 years ago, renowned physicists formulated theoretical models for the electronic structure of liquid metals. Now, for the first time, researchers observed the distinct spectral features predicted by those models, at the interface of a crystalline insulator (black phosphorus) and disordered dopants (alkali metals). Read more »
Autonomous Data Acquisition for Scientific Discovery
Researchers at large scientific facilities such as the ALS have applied a robust machine-learning technique to automatically optimize data gathering for a variety of experimental techniques. The work promises to enable experiments with large, complex datasets to be run more quickly, efficiently, and with minimal human intervention. Read more »