Professor Dirk van der Marel’s team from the Department of Quantum Matter Physics (DQMP) of Geneva University recently discovered a whole new effect in a magnetic material with a chemical composition of Nd2Ir2O7. At absolute zero (-273.15 degrees Celsius), this material is insulating but by increasing its temperature it becomes an electrical conductor. More precisely,…
By Prof. Gabriel Aeppli, ETHZ, EPFL and PSI Among the most important problems illuminated by the current COVID-19 pandemic are those of producing and measuring the immune response to the corona virus. The immune response defines the progression and lethality of the disease in an infected individual, while the idea of promoting such a response through…
The crystal structure of a drug tested against Covid-19 was solved using Fox computer program, developed in the Laboratory of crystallography at the Department of quantum matter physics (DQMP), UNIGE. Recently, James Kaduk (Illinois Institute of Technology and North Central College) and collaborators Amy Gindhart and Thomas Blanton (International Centre for Diffraction Data, ICDD) have…
Matteo Alessandrini’s group at Bruker BioSpin and Prof. Senatore’s group at DQMP, University of Geneva have been recently awarded financial support by Innosuisse for a 3 years project. The project will start in September 2020. The title of the project is “HTS superconducting joints for NMR magnets”. This project aims to develop superconducting HTS joints made for application…
By Ana Akrap, Université de Fribourg Based on article published in Physical Review Materials Transition metal dichalcogenides are a rich and diverse family of compounds. In both bulk and few-layer form, transition metal dichalcogenides are intensely studied for many of their interesting properties: excitons, superconductivity, and band-gap tuning by thickness. They are also pursued for their potential…
By Tian Shang, Paul Scherrer Institut Based on article published in Physical Review Letters The study of unconventional superconductors is of great interest to the physics community. Complex superconducting ground states can form the basis of novel quantum-field theories and have the potential for applications ranging from particle accelerators to quantum computers. The ongoing interest in…
To achieve optimal virus detection using surface plasmon resonance (SPR), a leading SPR manufacturer is relying on glass prisms with a high-quality gold thin film sensor custom grown in the LTA laboratory (Fig.1). Basic research provides the basis for subsequent applied research and development. In the same way, instrumentation and expertise tailored for basic research…
Researchers from UNIGE and the University of Manchester have discovered structures based on two-dimensional materials that emit tailor-made light in any colour you could wish for. Finding new semi-conductor materials that emit light is essential for developing a wide range of electronic devices. But making artificial structures that emit light tailored to our specific needs…
By Manfred Sigrist, ETHZ This year in May the 25th anniversary of the discovery of Sr2RuO4 was celebrated with a dedicated workshop at ETH Zurich. Sr2RuO4 has been the second superconductor found in the class of perovskite transition metal oxides after the cuprates and has ever since played an important role in the field of…
By Jennifer Fowlie Based on article published in Nano Letters X-ray diffraction is a ubiquitous tool used in many areas of physical sciences for determining the structure of matter. There are two particular experimental challenges in measuring an x-ray diffraction signal; samples that are of too small a volume and atoms that are of too…
By Junzhang Ma, Paul Scherrer Institute Based on article published in Science Advances The realization of Weyl semimetals (WSMs) with time-reversal symmetry broken is one of the central issues in the research of novel topological phases in condensed matter. Weyl semimetals are one kind of exotic materials that host massless doubly degenerate Weyl fermions in…
The Laboratory of Advance Technology (LTA) in Geneva has launched a new platform for chemical analysis and imaging. Open to both academics and industry, this platform provides access to a nano-TOF SIMS and an XPS, and is the only lab in Switzerland to provide access to both of these complementary techniques. Together, they…
This platform is now open to both academic and industrial laboratories. Discover more at the XPS and TOF-SIMS seminar on November 14th. This platform, unique in Switzerland, combines expertise in molecular identification and surface chemistry with two state-of-the-art systems: a TOF-SIMS mass spectrometer and a scanning XPS microprobe. These two complementary techniques allow sensitive and…
Some time ago, Christophe Berthod from the University of Geneva met Gilles Bellevaut, who is interested in science and shares his scientific explorations in the form of comic strips. Recently, they visited together the ARPES/STM laboratory of Prof. Philipp Aebi and Prof.Claude Monney from the University of Fribourg. Discover the story of this day in…
Researchers from the University of Geneva and the University of Manchester have confirmed experimentally the theory of very strong magneto-optical resonance in graphene. The ability to control infrared and terahertz waves using magnetic or electric fields is one of the great challenges in physics that could revolutionise opto-electronics, telecommunications and medical diagnostics. A theory from…
By Prof. Carmine Senatore, UNIGE and Prof. Leonid Rivkin, PSI Since the discovery of superconductivity in 1911, this phenomenon was greeted with high hopes for groundbreaking applications. However, scientists had to face many difficulties to develop these materials in a useful conductor form and yet only six – one alloy, two intermetallic compounds and three ceramic…
by Anna Tamai, University of Geneva based on an article published in Physical Review X Since the seminal work of Landau in the 1950’s, the low-temperature metallic state of materials is generally assumed to be well understood. Yet, when it comes to oxides, even good metals such as the strontium ruthenates continue to hold surprises.…
by Johan Chang, University of Zürich based on an article published in Nature Communications Exposed to pressure, the lattice parameters of a material generally shrink. In turn, the electronic nearest neighbour hopping integral t increases, due to larger orbital overlap. In a Mott insulator this enhancement can trigger a bandwidth-controlled insulator-to-metal transition. Indeed, the ratio, U/t, of…
By Prof. László Forró, EPFL Materials are the linchpin of technological progress. All energy related applications like photovoltaics, fuel cells, thermoelectrics, (harvesting, storing and transmitting) heavily depend on new, more performant materials. Even the success of energy production by nuclear fusion crucially relies on finding compounds that can withstand high doses of irradiation. Information technologies are…
by Björn Wehinger, UNIGE and PSI based on an article published in Physical Review Letters Quantum magnets have evolved over the past decade into systems of large interest in fundamental and, increasingly, in applied physics. Their exceptional properties, including non-magnetic ground states, fractionalised excitations and topological order, have become candidate resources for quantum information and computing. Application in spintronic…
by Jan Hugo Dil, EPFL based on an article published in Physical Review X The control of the electron spin in functional materials by an external electric field is a key issue for spintronic devices. Because the spin is not directly influenced by a realistic electric field, the coupling has to be indirect and thus especially…
Physicists from Rice University and the University of Geneva have verified a key prediction from a 55-year-old theory about one-dimensional electronics that is increasingly relevant thanks to Silicon Valley’s inexorable quest for miniaturization. “Chipmakers have been shrinking feature sizes on microchips for decades, and device physicists are now exploring the use of nanowires and nanotubes…
Predicting the behaviour of electrons in a material is not easily done. Physicists from the University of Geneva (UNIGE), ETH Zurich and EPFL replaced the electrons with ultra-cold neutral lithium atoms that they had circulated in a one-dimensional quantum tube. The scientists were then able to confirm an unusual state of matter that retains its…
Scilight from AIP Publishing is talking about a recent publication of Hugo Meley and coworkers in APL Materials. Moving from discovering physical properties to the ability to tailor them requires precise understanding and mastery of materials fabrication. This study unveils how the substrate affects the growth of crystalline vanadate thin films and the arrangement of their…
A unique cryogenic scanning near-field optical microscope (cryo-SNOM) has been installed at the DQMP and is now able to demonstrate the first promising results. In contrast to the conventional optical microscopes, in this system the sample is probed by the so called evanescent electromagnetic waves, which are emitted and detected by an ultrasharp metallized tip…
by Christophe Berthod, Ivan Maggio-Aprile, Christoph Renner, Department of Quantum Matter Physics, University of Geneva based on an article published in Physical Review Letters Copper oxide superconductors were the first to be found superconducting above liquid nitrogen temperature in the mid-1980s, thus shattering through the maximum critical temperature of 35K foreseen by theorists. The mechanism enabling…
by Daniel Mazzone, Paul Scherrer Institut based on an article published in Physical Review Letters Most superconducting condensates are accurately described within the scope of the BCS-theory (Bardeen-Cooper-Schrieffer), where electrons are bound together via virtual phonons. They are in strong contrast to so-called unconventional superconductors, in which the pairing mechanism is still unclear but thought to arise from magnetic…
In a superconductor, the electrons experience very peculiar interactions whose most surprising effect is a total loss of electrical resistance. These materials are therefore promising for future applications, especially since some of them work at the temperature of liquid nitrogen. The mechanism behind these exceptional properties remains mysterious, though. Studying these materials when they are…
by Björn Wehinger, Department of Quantum Matter Physics, University of Geneva based on an article published in Physical Review Letters Physicists from the University of Geneva and the European Synchrotron discovered how to obtain the full elasticity tensor from a single crystal diffraction experiment. Measurements of thermal diffuse scattering revealed that the complete set of…
by Mickaël Morin and Marisa Medarde, Paul Scherrer Institut based on an article published in Nature Communications In the past years, magnetism-driven ferroelectricity has been reported in a number of frustrated magnets with spiral magnetic orders. Such materials are of high current interest due to their potential for spintronics and low-power magnetoelectric devices. However, their low…
The terahertz waves span frequency ranges between the infrared spectrum (used, for example, for night vision) and gigahertz waves (which find their application, among other, in Wi-Fi connections). Terahertz waves allow for the detection of materials that are undetectable at other frequencies. However, the use of these waves is severely limited by the absence of…
by Sebastian Manz and Manfred Fiebig, ETH Zürich based on an article published in Nature Photonics Antiferromagnetism is magnetic order, yet without a macroscopic magnetization as in iron. The absence of the field has interesting technological potential, but it also makes the antiferromagnetic state harder to control and set in a certain direction.…
by Tomáš Bzdušek, Department of Physics, ETH Zürich based on an article published in Nature The microscopic distinction between ordinary insulators and metals is understood since the early years of quantum mechanics by the so-called band theory. Semimetals form a natural boundary between the two, and they attracted much attention in recent years due to their unusual…
by Luc Patthey, PSI (Paul Scherrer Institut) The new Swiss Free Electron Laser facility SwissFEL is a unique light source which will provide new opportunities for cutting-edge research, and aims at providing solutions to important scientific and technological challenges facing modern society in the fields of Matter and Materials, Energy and the Environment, and Human Health. SwissFEL…
Marta Gibert receives the Swiss Physical Society (SPS) Prize sponsored by IBM for her research on magnetic coupling at oxide interfaces, particularly in the interface engineering of heterostructures combining nickelates and manganites. The results led to the publications: “Exchange bias in LaNiO3–LaMnO3 superlattices“, M. Gibert, et al., Nature Materials 11, 195 (2012). “Interfacial Control of Magnetic Properties…
Some materials hold surprising — and possibly useful — properties: Neodymium nickel oxide is either a metal or an insulator, depending on temperature. This characteristic makes the material a potential candidate for transistors in modern electronic devices. To understand how neodymium nickel oxide makes the transition from metal to insulator and vice versa, researchers at…
Crystalline solids have particlelike, low-energy excitations — so-called quasiparticles — that describe collective states of many electrons interacting with the atomic nuclei. In 2015, scientists predicted the existence of an exotic new quasiparticle, dubbed a type-II Weyl fermion, that breaks the Lorentz invariance of special relativity and has no direct analog in the standard model…
Superconductivity with a high critical temperature (high Tc) continues to present a theoretical mystery. While this phenomenon is experimentally well established, no scientist has managed to explain its mechanism. In the late 90’s, the British physicist Anthony Leggett proposed a scenario based on the Coulomb energy. Today, researchers at the University of Geneva (UNIGE), Switzerland,…
By Pieter J. de Visser and Alexey B. Kuzmenko, Department of Quantum Matter Physics, UNIGE After an article published in Physical Review Letters In electronics and photonics there is a continuous quest for novel ways to excite and manipulate electrons in materials due to interaction with light. A recent development is valleytronics, in which the…
An international collaboration involving researchers from the University of Geneva, and colleagues from England, Spain, France and Luxembourg has demonstrated that destabilising the spontaneous polarisation of a special class of materials known as ferroelectrics gives rise to the phenomenon of negative capacitance that could one day lead to transistors with reduced power consumption. This research…
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