Phys.org August 15, 2024 Copper oxide materials can be made superconducting by doping the parent compound with either electrons or holes. Hole-doped cuprates typically have higher transition temperatures and have been studied more extensively. An international team of researchers (SLAC National Accelerator Laboratory, Yale University, UC Berkeley, Sweden) observed an unusual energy gap in electron-doped cuprate Nd2-xCexCuO4 high above the temperature of the superconducting transition. After considering all the known ordering tendencies in tandem with the phase diagram, they hypothesized that the normal-state gap in the underdoped n-type cuprates originated from Cooper pairing. According to the researchers the high temperature […]
Category Archives: Materials science
Specialized materials could passively control the internal temperature of space habitats
Phys.org August 19, 2024 Researchers in Spain explored the design of a space habitat thermally controlled using phase change materials (PCMs) to maintain a suitable, habitable temperature inside the habitat by isolating it from the external solar radiation. They studied the system numerically considering only diffusive heat transport scenario with practical application to microgravity or reduced gravity environments. The system dynamics were explored for a wide range of governing parameters, including the length of the PCM cell L, the thermo-optical properties at the external boundary of the habitat wall exposed to solar radiation, the eclipse fraction of the solar cycle, […]
2D layer of phosphorus pentamers shows semiconductor properties on silver surface
Phys.org August 9, 2024 An international team of researchers (Switzerland, Chia) characterized the atomic structure of cyclo-P5 assembled on Ag(111). They found that a strong charge transfer induced an inward dipole moment at the cyclo-P5/Ag interface as well as the formed an interface state. They probed the image potential states and quantified the increase of the local change of work function. According to the researchers their approach suggested that the cyclo-P5/Ag interface has the characteristic ingredients of a p-type semiconductor-metal Schottky junction with potential applications in field-effect transistors, diodes, or solar cells… read more. Open Access TECHNICAL ARTICLE
Researchers discover new material for optically-controlled magnetic memory
Phys.org August 9, 2024 The indirect exchange interaction between local magnetic moments via surface electrons has been long predicted to bolster the surface ferromagnetism in magnetic topological insulators (MTIs), which facilitates the quantum anomalous Hall effect. This unconventional effect is critical to determining the operating temperatures of future topotronic devices. However, the experimental confirmation of this mechanism has not been investigated in intrinsic MTIs. An international team of researchers (University of Chicago, University of Florida, Pennsylvania State University, Israel) combined time-resolved photoemission spectroscopy with time-resolved magneto-optical Kerr effect measurements to explain the unique electromagnetism at the surface of an intrinsic […]
Lasers deliver powerful shocking punch in material experiments
Phys.org August 7, 2024 A team of international researchers (Stanford University, Lawrence Livermore National Laboratory, Purdue University, Carnegie Mellon University, SLAC National Accelerator Laboratory, Germany) used diffraction patterns from x-ray pulses to investigate the temperature evolution of laser-shocked Al–Zr metal film composites at time delays ranging from 5 to 75 ns driven by a short-pulse laser. They found significant heating of both Al and Zr after shock release. A conventional hydrodynamic model did not fully account for the measured temperature increase, which suggested that other strength-related mechanisms (such as fine-scale void growth) could play an important role in thermal responses under […]
Ice 0: Researchers discover a new mechanism for ice formation
Phys.org July 26, 2024 The role of the free surface of water in nucleation process remains unclear. Researchers in Japan investigated the microscopic freezing process using molecular dynamics simulations and found that the free surface assisted ice nucleation through an unexpected mechanism. The surface-induced negative pressure enhanced the formation of local structures with a ring topology characteristic of Ice 0-like symmetry, and promoted ice nucleation despite the symmetry differing from ordinary ice crystals. Unlike substrate-induced nucleation via water-solid interactions that occurs directly on the surface, this negative-pressure-induced mechanism promoted ice nucleation slightly inward the surface. Their findings provided a molecular-level […]
An MRI-like tool for quantum materials: Sensor can detect minute magnetic fields at atomic scale
Phys.org July 25, 2024 The detection of faint magnetic fields from single-electron and nuclear spins at the atomic scale is a long-standing challenge in physics. While current mobile quantum sensors achieve single-electron spin sensitivity, atomic spatial resolution remains elusive for existing techniques. An international team of researchers (Germany, South Korea) fabricated a single-molecule quantum sensor at the apex of the metallic tip of a scanning tunnelling microscope by attaching Fe atoms and a PTCDA (3,4,9,10-perylenetetracarboxylic-dianhydride) molecule to the tip apex. They addressed the molecular spin by electron spin resonance and achieved ~100 neV resolution in energy. In a proof-of-principle experiment, they […]
When copper becomes transparent: European XFEL creates exotic matter
Phys.org July 29, 2024 To understand its electronic structure and structure upon irradiation with strong laser pulses, an international team of researchers (Germany, Slovenia, Sweden, Switzerland, Poland, USA – University of Washington) simultaneously created and characterized warm dense copper over a large irradiation intensity range. An absorption peak below the L edge appeared from transient depletion of the 3d band. The peak shifted to lower energy with increasing intensity, indicating the movement of the 3d band upon strong X-ray excitation. At higher intensities, substantial ionization and collisions led to the transition from reverse saturable absorption to saturable absorption of the […]
Aluminum scandium nitride films: Enabling next-gen ferroelectric memory devices
Phys.org July 19, 2024 By subjecting the films to post-heat-treatment at various temperatures up to 600 °C in both H2 and Ar gases Researchers in Japan investigated the changes in the crystal structure and ferroelectric properties of aluminum scandium nitride films sandwiched between platinum and titanium nitride and titanium nitride electrodes. The remanent polarization underwent slight change, whereas the coercive field was strengthened by approximately 9% because of the post-heat-treatment up to 600 °C irrespective of the atmosphere and electrode material. This change was much smaller than that reported for ferroelectric zirconium dioxide films as well as for lead zirconate titanate and […]
Machine learning unlocks secrets to advanced alloys
MIT News July 18, 2024 The tendency of certain chemical motifs to be more common than others is known as chemical short-range order (SRO), and it has received substantial consideration in alloys with multiple chemical elements present in large concentrations due to their extreme configurational complexity. SRO renders solid solutions “slightly less random than completely random,” but not easily quantifiable due to the sheer number of possible chemical motifs and their subtle spatial distribution on the lattice. Researchers at MIT presented a multiscale method to predict and quantify the SRO state of an alloy with atomic resolution, incorporating machine learning […]