/ en-us Â鶹ÒùÔº internet news portal provides the latest news on science including: Â鶹ÒùÔºics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine. The candidate pool for engineered materials that can help enable tomorrow's cutting-edge optical technologies—such as lasers, detectors and imaging devices—is much deeper than previously believed. /news/2025-06-pathways-previously-thought-optical-topological.html Optics & Photonics Tue, 24 Jun 2025 15:55:04 EDT news669999301 Metal-organic frameworks (MOFs) are characterized by high porosity and structural versatility. They have enormous potential, for example, for applications in electronics. However, their low electrical conductivity has so far greatly restricted their adoption. /news/2025-06-metal-frameworks-metallic-pave-paths.html Nanophysics Nanomaterials Tue, 24 Jun 2025 15:49:04 EDT news669998942 Topological insulators (TIs) are among the hottest topics in condensed matter physics today. They're a bit strange: Their surfaces conduct electricity, yet their interiors do not, instead acting as insulators. Â鶹ÒùÔºicists consider TIs the materials of the future because they host fascinating new quantum phases of matter and have promising technological applications in electronics and quantum computing. Scientists are just now beginning to uncover connections between TIs and magnetism that could unlock new uses for these exotic materials. /news/2025-01-illuminating-asymmetric-gap-topological-antiferromagnet.html Condensed Matter Quantum Â鶹ÒùÔºics Tue, 21 Jan 2025 16:47:15 EST news656700425 A new study, published in a recent issue of Nature Â鶹ÒùÔºics, sheds light on the long-anticipated emergence of quasiparticles, akin to the famous Dirac particles obeying the relativistic Dirac equation. These quasiparticles, known as Dirac spinons, were theorized to exist within a novel quantum state called a quantum spin liquid state. /news/2024-05-spectral-evidence-dirac-spinons-kagome.html Condensed Matter Quantum Â鶹ÒùÔºics Mon, 13 May 2024 09:29:03 EDT news634811341 Chiral zeroth Landau levels are topologically protected bulk states that propagate in a single direction. In the field of quantum field theory and condensed matter physics, these levels are crucial for breaking chiral symmetry and triggering the chiral anomaly, which involves the non-conservation of chiral currents in both particle physics and condensed matter systems. /news/2023-07-inhomogeneous-dirac-cone-in-plane-chiral.html Optics & Photonics Quantum Â鶹ÒùÔºics Fri, 07 Jul 2023 13:41:03 EDT news607956061 Starting with the emergence of quantum mechanics, the world of physics has been divided between classical and quantum physics. Classical physics deals with the motions of objects we typically see every day in the macroscopic world, while quantum physics explains the exotic behaviors of elementary particles in the microscopic world. /news/2023-01-scientists-quasiparticles-classical.html General Â鶹ÒùÔºics Quantum Â鶹ÒùÔºics Thu, 26 Jan 2023 13:09:08 EST news593960941 The introduction of topology in photonic systems has attracted considerable attention not only for the elaborate molding of light but also for its practical applications in novel photonic devices. Originally, the quantum Hall effect of light was realized in photonic crystals (PCs) by introducing external electric or magnetic fields to break the time-reversal symmetry (TRS). /news/2022-09-dual-polarization-two-dimensional-valley-photonic-crystals.html Optics & Photonics Fri, 02 Sep 2022 13:28:03 EDT news581344081 Graphene consists of carbon atoms that crosslink in a plane to form a flat honeycomb structure. In addition to surprisingly high mechanical stability, the material has exciting electronic properties. The electrons behave like massless particles, which can be clearly demonstrated in spectrometric experiments. Measurements reveal a linear dependence of energy on momentum, namely the so-called Dirac cones—two lines that cross without a band gap—an energy difference between electrons in the conduction band and those in the valence bands. /news/2022-07-buckyballs-gold-exotic-graphene.html Nanomaterials Thu, 21 Jul 2022 13:59:02 EDT news577630741 A team of scientists have "velcroed" 2D structures of MoS2 and graphene using a covalent connection for the first time. The 2D-2D structures were used to build robust field effect transistors with controlled electronic communication, interface chemical nature and interlayer distance. /news/2022-04-van-der-waals-covalent-2d-2d.html Nanomaterials Thu, 28 Apr 2022 12:02:23 EDT news570366140 Researchers have used direct chemical vapor deposition (CVD) growth of wafer-scale, high-quality graphene on dielectrics for versatile applications. However, graphene synthesized this way has shown a polycrystalline film with uncontrolled defects, a low carrier mobility, and high street resistance; therefore, researchers aim to introduce new methods to develop wafer-scale graphene. In a new report now published in Science Advances, Zhaolong Chen and an international research team in nanochemistry, intelligent materials and physics, in China, U.K. and Singapore, described the direct growth of highly oriented monolayer graphene on films of sapphire wafers. They achieved the growth strategy by designing an electromagnetic induction CVD at elevated temperature. The graphene film developed in this way showed a markedly improved carrier mobility and reduced sheet resistance. /news/2021-12-wafer-scale-highly-graphene-sapphire.html Nanomaterials Wed, 01 Dec 2021 09:30:01 EST news557571066 A University of Wollongong-led team across three FLEET nodes has combined two traditional semiconductor doping methods to achieve new efficiencies in the topological insulator bismuth-selenide (Bi2Se3). /news/2021-11-combine-semiconductor-doping-methods-efficiencies.html Condensed Matter Fri, 12 Nov 2021 09:39:41 EST news555932377 Diffraction is a natural property of light beams that allows light to bend around obstacles. Because light serves as a carrier of information, some of the distorting effects of diffraction must be mitigated for many technological applications. Topological insulators, first unveiled in condensed matter physics, have attracted interest for over a decade. A photonic topological insulator can help ensure consistent propagation of a light beam along its edges. Robust photonic edge states are key to developing on-chip photonic technology. /news/2021-10-topological-valley-hall-edge-solitons.html Optics & Photonics Tue, 26 Oct 2021 10:41:08 EDT news554463666 Scientists at the U.S. Department of Energy's Ames Laboratory have observed novel helical magnetic ordering in the topological compound EuIn2As2 which supports exotic electrical conduction tunable by a magnetic field. The discovery has significant implications for basic research into functional topological properties and may one day find use in a number of advanced technology applications. /news/2021-03-scientists-complex-tunable-magnetism-tied.html General Â鶹ÒùÔºics Quantum Â鶹ÒùÔºics Mon, 22 Mar 2021 09:07:51 EDT news535622868 Electrons in a solid occupy distinct energy bands separated by gaps. Energy band gaps are an electronic "no man's land," an energy range where no electrons are allowed. Now, scientists studying a compound containing iron, tellurium, and selenium have found that an energy band gap opens at a point where two allowed energy bands intersect on the material's surface. They observed this unexpected electronic behavior when they cooled the material and probed its electronic structure with laser light. Their findings, reported in the Proceedings of the National Academy of Sciences, could have implications for future quantum information science and electronics. /news/2021-03-magnetism-topology-superconductor-surface.html Superconductivity Quantum Â鶹ÒùÔºics Wed, 17 Mar 2021 10:08:09 EDT news535194485 A refractive index of zero induces a wave vector with zero amplitude and undefined direction. Therefore, light propagating inside a zero-index medium does not accumulate any spatial phase advance, resulting in perfect spatial coherence. Such coherence brings several potential applications, including arbitrarily shaped waveguides, phase-mismatch-free nonlinear propagation, large-area single-mode lasers, and extended super radiance. A promising platform to achieve these applications is an integrated Dirac-cone material that features an impedance-matched zero index. However, although this platform eliminates ohmic losses via its purely dielectric structure, it still entails out-of-plane radiation loss (about 1 dB/μm), restricting the applications to a small scale. /news/2021-01-applications-ultra-low-loss-on-chip-zero-index-materials.html Optics & Photonics Fri, 15 Jan 2021 13:42:02 EST news529940519 The elementary particles that build the universe have two types: bosons and fermions, where the fermions are classified as Dirac, Weyl, and Majorana fermions. In recent years, Weyl fermions are found in condensed matter systems, and Weyl semimetals as a kind of quasiparticle, and they manifest themselves as Weyl points from dispersion relations. In contrast to high-energy physics which requires the stringent Lorentz symmetry, there are two types of Weyl points in condensed matter systems: type-I Weyl points with symmetric cone-like band structures and type-II Weyl points with strongly tilted band structures. /news/2020-11-ideal-type-ii-weyl-classical-circuits.html Condensed Matter Wed, 25 Nov 2020 10:20:12 EST news525522008 Scientists at Tokyo Institute of Technology shed light on the relationship between the magnetic properties of topological insulators and their electronic band structure. Their experimental results offer new insights into recent debates regarding the evolution of the band structure with temperature in these materials, which exhibit unusual quantum phenomena and are envisioned to be crucial in next-generation electronics, spintronics, and quantum computers. /news/2020-09-bridging-gap-magnetic-electronic-properties.html General Â鶹ÒùÔºics Condensed Matter Thu, 24 Sep 2020 12:50:01 EDT news520170208 An Australian-led study uses a scanning-tunneling microscope "trick" to map electronic structure in Na3Bi, seeking an answer to that material's extremely high electron mobility. /news/2020-08-unexpectedly-fast-electrons-na3bi.html Quantum Â鶹ÒùÔºics Mon, 17 Aug 2020 09:05:35 EDT news516873932 It sounds like pure sorcery: using diamonds to observe invisible power swirling and flowing through carefully crafted channels. But these diamonds are a reality. JQI Fellow Ronald Walsworth and Quantum Technology Center (QTC) Postdoctoral Associate Mark Ku, along with colleagues from several other institutions, including Professor Amir Yacoby and Postdoctoral Fellow Tony Zhou at Harvard, have developed a way to use diamonds to see the elusive details of electrical currents. /news/2020-07-diamonds-hidden-currents-graphene.html Nanophysics Wed, 22 Jul 2020 11:00:09 EDT news514617639 Nontrivial band topology can combine with magnetic order in a magnetic topological insulator to produce exotic states of matter such as quantum anomalous Hall (QAH) insulators and axion insulators. An aim of condensed matter physics is to find new materials with useful properties and apply quantum mechanics to study them. The field has allowed physicists to better understand the uses of magnets for hard disk data storage, computer displays and other technologies. The recent discovery of topological insulators have attracted broad interest and researchers predict that the interplay between ferromagnetism and the topological insulator state can realize a range of exotic quantum magnetic phenomena of interest in fundamental physics and device applications. /news/2020-02-quantum-anomalous-hall-effect-intrinsic.html Quantum Â鶹ÒùÔºics Thu, 13 Feb 2020 09:30:02 EST news500800253 In a new report on Science Advances, Chen Fang and Liang Fu from the Beijing National Laboratory for Condensed Matter Â鶹ÒùÔºics in China, Kavli Institute for Theoretical Sciences and the Department of Â鶹ÒùÔºics, Massachusetts Institute of Technology in the U.S. Detailed the discovery of new types of quantum anomalies in two-dimensional systems with time-reversal symmetry (T) (conservation of entropy) and discrete rotation symmetry; where a shape retains the same structure after rotation by a partial turn and order. They then physically realized anomalous states on the surface of new classes of topological crystalline insulators (TCIs) normal to the rotation axis and supporting a helical mode. The presence of helical modes allowed them to form a new quantum device from a topological crystalline insulator known as a helical nanorod with quantized longitudinal conductance. /news/2020-01-classes-topological-crystalline-insulators-surface.html Condensed Matter Quantum Â鶹ÒùÔºics Tue, 14 Jan 2020 09:30:02 EST news498126605 When a metal is heated to a sufficiently high temperature, electrons can be ejected out from the surface in a process known as the thermionic emission, a process that is similar to the evaporation of water molecules from the surface of boiling water. /news/2019-10-physicists-mystery-thermionic-emissions-graphene.html Nanomaterials Mon, 07 Oct 2019 11:17:34 EDT news489665839 Transition metal dichalcogenides (TMDCs) formed by group 10 metals (e.g. PtSe2, PtTe2) have emerged as important materials with intriguing properties discovered both in bulk single crystals and atomically thin films. While bulk PtSe2 and PtTe2 are type-II Dirac semimetals, monolayer (ML) PtSe2 film is a semiconductor with helical spin texture induced by local Rashba effect. However, the properties of atomically thin PtTe2 films and the evolution with film thickness remain unexplored. Recently, Shuyun Zhou's group from Tsinghua University reported a systematic study on the electronic structure of high quality PtTe2 thin films with thickness from 2 ML to 6 ML grown by molecular beam epitaxy (MBE). This work provides direct experimental evidence for a crossover from 2-D metal (2ML film, distinguished from the semiconducting PtSe2 film) to 3-D Dirac semimetal in PtTe2 films with spin texture induced by local Rashba effect. /news/2019-08-crossover-d-metal-dirac-semimetal.html Nanophysics Nanomaterials Tue, 20 Aug 2019 11:14:01 EDT news485518436 The search for better materials for computers and other electronic devices has focused on a group of materials known as "topological insulators" that have a special property of conducting electricity on the edge of their surfaces like traffic lanes on a highway. This can increase energy efficiency and reduce heat output. /news/2019-08-uncover-hidden-topological-insulator-states.html General Â鶹ÒùÔºics Quantum Â鶹ÒùÔºics Wed, 07 Aug 2019 08:07:15 EDT news484384028 Topological insulators are one of the most exciting discoveries of the 21st century. They can be simply described as materials that conduct electricity on their surface or edge, but are insulating in their interior bulk. Their conductive properties are based on spin, a quantum mechanical property, and this suppresses the normal scattering of electrons off impurities in the material, or other electrons, and the amount of energy that is consequently lost to heat. In contrast to superconductors, topological insulators can work at room temperature, offering the potential for our current electronics to be replaced with quantum computers and 'spintronic' devices that would be smaller, faster, more powerful and more energy efficient. Topological insulators are classified as 'strong' or 'weak', and experimental confirmations of the strong topological insulator (STI) rapidly followed theoretical predictions. However, the weak topological insulator (WTI) was harder to verify experimentally, as the topological state emerges on particular side surfaces, which are typically undetectable in real 3-D crystals. In research recently published in Nature, a team of researchers from Japan used synchrotron techniques to provide experimental evidence for the WTI state in a bismuth iodide crystal. /news/2019-04-weak-topological-insulator-bismuth-iodide.html Condensed Matter Thu, 18 Apr 2019 10:06:27 EDT news474800782 At the turn of the 20th century, scientists discovered that atoms were composed of smaller particles. They found that inside each atom, negatively charged electrons orbit a nucleus made of positively charged protons and neutral particles called neutrons. This discovery led to research into atomic nuclei and subatomic particles. /news/2019-04-big-tiny-particles.html General Â鶹ÒùÔºics Fri, 05 Apr 2019 09:06:36 EDT news473673422 A simple sheet of graphene has noteworthy properties due to a quantum phenomenon in its electron structure called Dirac cones. The system becomes even more interesting if it comprises two superimposed graphene sheets, and one is very slightly turned in its own plane so that the holes in the two carbon lattices no longer completely coincide. For specific angles of twist, the bilayer graphene system displays exotic properties such as superconductivity. /news/2018-11-artificial-magnetic-field-exotic-behavior.html Nanophysics Fri, 30 Nov 2018 08:03:40 EST news462787414 The research focus on 2-D materials has intensified with its potential to modulate light for superior performance and realize applications that can enhance existing technologies. Graphene, the best known 2-D material, derived from 3-D graphite, constitutes a monolayer of carbon atoms arranged in a 2-D hexagonal lattice, exhibiting strong ultra-wideband light-matter interactions, able to operate at an extremely broad spectral range, suited for next-generation photonics and optoelectronic devices. The unique electronic properties of graphene originate from Dirac cones, features in electronic band structures that host charge carriers of zero effective mass, so-called massless Dirac fermions that occur in 2-D materials. Materials scientists are currently at a stage of experimental infancy to realize many interesting properties of the nonlinear optical responses of graphene, to aid its promise to disrupt existing technology and facilitate wide-ranging applications. /news/2018-08-electrically-tunable-third-order-nonlinear-optical.html Nanophysics Wed, 01 Aug 2018 09:30:03 EDT news452330749 A research team led by Pham Nam Hai at the Department of Electrical and Electronic Engineering, Tokyo Institute of Technology (Tokyo Tech) has developed the world's best-performing pure spin current source made of bismuth-antimony (BiSb) alloys, which they report as the best candidate for the first industrial application of topological insulators. The achievement represents a big step forward in the development of spin-orbit torque magnetoresistive random-access memory (SOT-MRAM) devices with the potential to replace existing memory technologies. /news/2018-08-bisb-potential-topological-insulators-ultra-low-power.html Condensed Matter Wed, 01 Aug 2018 05:51:40 EDT news452321490 The basic quanta of light (photon) and sound (phonon) are bosonic particles that largely obey similar rules and are in general very good analogs of one another. Â鶹ÒùÔºicists have explored this analogy in recent experimental investigations of a phonon laser to provide insights into a long-debated issue of how a laser—or more specifically, its line width—is affected when operated at an exceptional point (EP). Exceptional points are singularities in the energy functions of a physical system at which two light modes coalesce (combine into one mode) to produce unusual effects. Until recently, the concept mainly existed only in theory, but received renewed attention with experimental demonstrations in optical systems such as lasers and photonic structures. The experimental studies involved systems with parity-time symmetry for balanced gain and loss of material, to ensure robust light intensity, immune to backscatter. While closed and lossless physical systems are described by Hermitian operators in quantum physics, systems with open boundaries that exhibit exceptional points (EPs) are non-Hermitian. /news/2018-07-phonon-laser-exceptional.html Optics & Photonics Fri, 20 Jul 2018 10:20:01 EDT news451294755