| An international research team, led by scientists from the EMPA (Zurich) and the International Iberian Nanotechnology Laboratory, which has researchers from the UPV/EHU, has succeeded in building chains of quantum magnets made of nanographene that capture the essence of one of the core models of quantum magnetism. The team’s results (Nature, “Observation of fractional edge excitations in nanographene spin chains”) have implications for understanding quantum magnetism on the nanoscale and may open the door to building quantum computers. | |
| We are all used to the idea that simple units combine to form more complex structures. So atoms combine to form molecules, which in turn combine to form cells, and cells form tissue, ultimately giving rise to living beings. | |
| In the quantum world, this process may take place in reverse in such a way that the interaction between complex particles results in simpler particles. So, under certain circumstances, the interaction between electrons, indivisible particles with electric charge e, gives rise to the emergence of particles with charge e/3. This phenomenon is known as fractionalization. | |
Quantum magic: fractionalizing spins |
|
| All elementary particles have intrinsic properties such as mass or charge that are intuitive to us, and others such as spin, which can be visualised like a compass. However, unlike normal compasses, which can point in any direction, the spin of quantum systems is quantized, and can only assume a discrete set of values. For example, we say that the spin of an electron is ½ and can only take two values. Particles with spin 1 can take three values. | |
| In the 1980s the British physicist Duncan Haldane built a mathematical model for spin 1 particles in which the fractionalization of the spins took place. So when a one-dimensional chain of indivisible spin 1 particles interacted with their neighbours, they gave rise to the emergence of spin ½ particles on the edges of the chain. | |
| Like the magic trick in which the magician saws a person in half and pulls the two halves apart, the Haldane model allows spins 1 to be fractionalized and separated. It is one of the core models of quantum magnetism, and his work earned him the Nobel Prize in 2016. | |
One-dimensional chains of magnetic molecules assembled from graphene |
|
| Experimental confirmation of this prediction was challenging for various reasons, chief among them being the fact that one-dimensional materials do not exist. Indirect evidence of the phenomenon of spin fractionalization in organometallic materials containing chains of magnetic atoms existed, but direct observation remained elusive. | |
| Now, however, that observation has been made by an international team of researchers, including the Ikerbasque researcher David Jacob of the Department of Polymers and Advanced Materials: Physics, Chemistry and Technology at the UPV/EHU; he has collaborated in this work with the INL, the University of Alicante, the EMPA in Zurich and the University of Dresden. | |
| To accomplish this difficult feat, the researchers combined organic chemistry techniques with ultra-high vacuum surface science in order to synthesise graphene molecules with spin 1 that form unidimensional chains. Using a tunnelling microscope, the team of researchers were able to study, with atomic resolution, the quantum states of the chain adsorbed on a gold surface, compare them with those predicted by the theory, and establish that the system did in fact behave like the Haldane model. | |
| In particular, in chains with a sufficiently high number of magnetic molecules, the researchers found Kondo resonances at the tips of the chain, a phenomenon that occurs when spin ½ particles interact with the electrons in a conductor such as gold. From one-dimensional chains to two-dimensional networks and quantum computers | |
| The researchers say that this work “shows the potential for using nanographenes to form two-dimensional networks of nanomagnets, enabling predictions analogous to Haldane’s to be confirmed, such as, for example, the existence of quantum states that would allow quantum computation to be carried out”. |
News
How nanomedicine and AI are teaming up to tackle neurodegenerative diseases
When I first realized the scale of the challenge posed by neurodegenerative diseases, such as Alzheimer's, Parkinson's disease and amyotrophic lateral sclerosis (ALS), I felt simultaneously humbled and motivated. These disorders are not caused [...]
Self-Organizing Light Could Transform Computing and Communications
USC engineers have demonstrated a new kind of optical device that lets light organize its own route using the principles of thermodynamics. Instead of relying on switches or digital control, the light finds its own [...]
Groundbreaking New Way of Measuring Blood Pressure Could Save Thousands of Lives
A new method that improves the accuracy of interpreting blood pressure measurements taken at the ankle could be vital for individuals who are unable to have their blood pressure measured on the arm. A newly developed [...]
Scientist tackles key roadblock for AI in drug discovery
The drug development pipeline is a costly and lengthy process. Identifying high-quality "hit" compounds—those with high potency, selectivity, and favorable metabolic properties—at the earliest stages is important for reducing cost and accelerating the path [...]
Nanoplastics with environmental coatings can sneak past the skin’s defenses
Plastic is ubiquitous in the modern world, and it's notorious for taking a long time to completely break down in the environment - if it ever does. But even without breaking down completely, plastic [...]
Chernobyl scientists discover black fungus feeding on deadly radiation
It looks pretty sinister, but it might actually be incredibly helpful When reactor number four in Chernobyl exploded, it triggered the worst nuclear disaster in history, one which the surrounding area still has not [...]
Long COVID Is Taking A Silent Toll On Mental Health, Here’s What Experts Say
Months after recovering from COVID-19, many people continue to feel unwell. They speak of exhaustion that doesn’t fade, difficulty breathing, or an unsettling mental haze. What’s becoming increasingly clear is that recovery from the [...]
Study Delivers Cancer Drugs Directly to the Tumor Nucleus
A new peptide-based nanotube treatment sneaks chemo into drug-resistant cancer cells, providing a unique workaround to one of oncology’s toughest hurdles. CiQUS researchers have developed a novel molecular strategy that allows a chemotherapy drug to [...]
Scientists Begin $14.2 Million Project To Decode the Body’s “Hidden Sixth Sense”
An NIH-supported initiative seeks to unravel how the nervous system tracks and regulates the body’s internal organs. How does your brain recognize when it’s time to take a breath, when your blood pressure has [...]
Scientists Discover a New Form of Ice That Shouldn’t Exist
Researchers at the European XFEL and DESY are investigating unusual forms of ice that can exist at room temperature when subjected to extreme pressure. Ice comes in many forms, even when made of nothing but water [...]
Nobel-winning, tiny ‘sponge crystals’ with an astonishing amount of inner space
The 2025 Nobel Prize in chemistry was awarded to Richard Robson, Susumu Kitagawa and Omar Yaghi on Oct. 8, 2025, for the development of metal-organic frameworks, or MOFs, which are tunable crystal structures with extremely [...]
Harnessing Green-Synthesized Nanoparticles for Water Purification
A new review reveals how plant- and microbe-derived nanoparticles can power next-gen water disinfection, delivering cleaner, safer water without the environmental cost of traditional treatments. A recent review published in Nanomaterials highlights the potential of green-synthesized nanomaterials (GSNMs) in [...]
Brainstem damage found to be behind long-lasting effects of severe Covid-19
Damage to the brainstem - the brain's 'control center' - is behind long-lasting physical and psychiatric effects of severe Covid-19 infection, a study suggests. Using ultra-high-resolution scanners that can see the living brain in [...]
CT scan changes over one year predict outcomes in fibrotic lung disease
Researchers at National Jewish Health have shown that subtle increases in lung scarring, detected by an artificial intelligence-based tool on CT scans taken one year apart, are associated with disease progression and survival in [...]
AI Spots Hidden Signs of Disease Before Symptoms Appear
Researchers suggest that examining the inner workings of cells more closely could help physicians detect diseases earlier and more accurately match patients with effective therapies. Researchers at McGill University have created an artificial intelligence tool capable of uncovering [...]
Breakthrough Blood Test Detects Head and Neck Cancer up to 10 Years Before Symptoms
Mass General Brigham’s HPV-DeepSeek test enables much earlier cancer detection through a blood sample, creating a new opportunity for screening HPV-related head and neck cancers. Human papillomavirus (HPV) is responsible for about 70% of [...]
