Category archives: Condensed matter

Nickel disulfide, NiS₂, is an unusual material. Its interior behaves as an electrical insulator, blocking the flow of current, while certain parts of its surface conduct electricity freely. This contradiction has puzzled physicists for decades, and a recent study offers a detailed explanation. The conduction, it turns out, is confined to tiny one-dimensional steps on […]

Researchers at Nagoya University have built a graphene nanoribbon that can switch which way it twists using a natural solvent. Graphene nanoribbons are thin ribbon-shaped structures made of fused carbon rings. Twisted or helical versions of these ribbons show promise for advanced light and electronic devices. However, no graphene nanoribbon could switch that twist on […]

One of the most striking discoveries in condensed matter physics over the past few years is that simply rotating one atomically thin crystal on top of an identical layer can create entirely new electronic behavior. This idea became famous in 2018, when physicists found that graphene sheets stacked at a very particular “magic angle” could […]

Many of today’s electronic devices — from the semiconductors in your cell phone to the photovoltaic cells in your solar panels — are built on thin-film substrates. The thin film is an electronically conductive material while the substrate is an inert material. Or is it? Physicists and materials scientists have long assumed substrates do not […]

Researchers at the University of Michigan have created a device that enables them to control the flow of electrons through a semiconductor using only laser light—no electrical power source required. This device was built to explore fundamental physics and realize a previously unobserved behavior, but it could also open doors for new applications in areas […]

Building electronic devices often requires stacking different crystalline materials on top of one another with atomic precision. This process, called heteroepitaxy, works best when the two crystals share similar atomic patterns. When their symmetries differ, the upper crystal tends to grow in several orientations at once instead of a single one, creating defects that degrade […]

Chirality is one of the most familiar ideas in science. Human hands are chiral because the left and right hand are mirror images that cannot be perfectly aligned on top of one another. The same idea appears in chemistry, where molecules with opposite handedness can behave very differently. In recent years, physicists have discovered that […]

In recent years, “twistronics” has shown that simply changing how two crystal layers sit on top of each other can completely transform their electronic behavior. When two lattices are slightly mismatched in size or rotated by a small angle, they create a larger repeating interference pattern called a moiré superlattice. This long-wavelength pattern acts like […]

In the world of quantum materials, some of the most important discoveries come not from finding new particles, but from learning to see familiar electrons in a new way. A striking example comes from a single layer of niobium diselenide, a crystal just one layer thick, where researchers have now directly mapped a hidden pattern […]

New research numerically demonstrates how carefully structured materials can control light in ways that are both precise and robust. It brings together ideas from photonics and topology to show how a laser can emerge from the boundary between two distinct optical regimes. The physical system considered in the study is a bilayer photonic crystal. A […]