Researchers achieve breakthrough in silicon-compatible magnetic whirls

Phys.org  February 20, 2024 Antiferromagnets hosting real-space topological textures are promising platforms to model fundamental ultrafast phenomena and explore spintronics. However, as they are epitaxially fabricated on specific symmetry-matched substrates, preserving their intrinsic magneto-crystalline order, curtails their integration with dissimilar supports, restricting the scope of fundamental and applied investigations. An international team of researchers (UK, Switzerland, Singapore) circumvented this limitation by designing detachable crystalline antiferromagnetic nanomembranes of α-Fe2O3. They showed that flat nanomembranes host a spin-reorientation transition and rich topological phenomenology. They demonstrated the reconfiguration of antiferromagnetic states across three-dimensional membrane folds resulting from flexure-induced strains. They combined these developments […]

Key innovation in photonic components could transform supercomputing technology

Phys.org  February 5, 2024 Researchers in South Korea demonstrated the array-level tunable couplers and phase shifters with capacitive electrostatic microelectromechanical actuators in a recirculating mesh network. The overall fabrication process was compatible with the conventional wafer-level passive silicon photonics platform. Extremely low unit-level standby power consumption of and reconfiguration energy with <11 V programming voltages offered well-balanced, scalable routes for efficient phase and amplitude modulation of the guided lightwaves with sub-decibel optical losses. The extinction ratios of the continuously tunable directional coupler exceed 30 dB. Full 2π-phase shifting could be achieved with a modulation efficiency of less than 0.075 V cm and a phase-dependent […]

Illuminating errors creates a new paradigm for quantum computing

Phys.org  October 11, 2023 For eventual application in quantum error correction, it is advantageous to realize qubits with structured error models, such as biased Pauli errors or conversion of errors into detectable erasures. An international team of researchers (USA – Princeton University, Yale University, France) demonstrated a new neutral atom qubit using the nuclear spin of a long-lived metastable state in 171Yb. The long coherence time and fast excitation to the Rydberg state allowed one- and two-qubit gates with fidelities of 0.9990(1) and 0.980(1), respectively. A large fraction of all gate errors results in decays out of the qubit subspace […]

Researchers advance topological superconductors for quantum computing

Nanowerk  September 21, 2023 The interface between 2D topological Dirac states and an s-wave superconductor is expected to support Majorana-bound states (MBS) that can be used for quantum computing applications. Realizing these novel states of matter and their applications requires control over superconductivity and spin-orbit coupling to achieve spin-momentum-locked topological interface states (TIS) which are simultaneously superconducting. A team of researchers in the US (Oak Ridge National Laboratory, Rutgers State University of New Jersey) have shown superconductivity in monolayer (ML) FeTe1–ySey (Fe(Te,Se)) grown on Bi2Te3 by molecular beam epitaxy (MBE). Spin and angle-resolved photoemission spectroscopy (SARPES) directly resolved the interfacial […]

Quantum material exhibits ‘non-local’ behavior that mimics brain function

Phys.org  August 8, 2023 A key aspect of how the brain learns and enables decision-making processes is through synaptic interactions. Electrical transmission and communication in a network of synapses are modulated by extracellular fields generated by ionic chemical gradients. Emulating such spatial interactions in synthetic networks can be of potential use for neuromorphic learning and the hardware implementation of artificial intelligence. A team of researchers in the US (Rutgers University, UC San Diego, Purdue University, Brookhaven National Laboratory, Argonne National Laboratory) has demonstrated that in a network of hydrogen-doped perovskite nickelate devices, electric bias across a single junction can tune […]

Team creates simple superconducting device that could dramatically cut energy use in computing

Phys.org  July 28, 2023 Accomplishing unequal supercurrents in the forward and backward directions in superconductors would enable unprecedented functionalities. This nonreciprocity of critical supercurrents is called the superconducting (SC) diode effect. An international team of researchers (USA – MIT, US Army DEVCOM, High School (Alabama, Washington). Switzerland, Spain) demonstrated the strong SC diode effect in conventional SC thin films, such as niobium and vanadium, employing external small magnetic fields. Interfacing the SC layer with a ferromagnetic semiconductor EuS, they further accomplished the nonvolatile SC diode effect reaching an efficiency of 65%. By careful control experiments and theoretical modeling, they demonstrated […]

Transferring data with many colors of light simultaneously

Nanowerk  June 29, 2023 Using light to send information between compute nodes can dramatically increase the available bandwidth while simultaneously decreasing energy consumption. Through wavelength-division multiplexing with chip-based microresonator Kerr frequency combs, independent information channels can be encoded onto many distinct colours of light in the same optical fibre for massively parallel data transmission with low energy. Although previous high-bandwidth demonstrations have relied on benchtop equipment for filtering and modulating Kerr comb wavelength channels, data-centre interconnects require a compact on-chip form factor for these operations. Researchers at Columbia University have demonstrated a massively scalable chip-based silicon photonic data link using […]

Optical memristors review: Shining a light on neuromorphic computing

Phys.org  June 5, 2023 In recent years, the ability to vary the conductance of a channel in electronics has enabled in-memory computing, thus leading to substantial interest in memristors. An international team of researchers (USA – University of Pittsburg, University of Maryland, Germany, UK) reviewed recent progress in this important and emerging aspect of photonic integrated circuits and provided an overview of the current state of the art. They shed light on the evolution of this technology—and the work that still needs to be done for it to reach its full potential. They have provided a comprehensive overview of recent […]

Discovery reveals ‘brain-like computing’ at molecular level is possible

Phys.org  November 21, 2022 An international team of researchers (Singapore, USA – University of Central Florida, the Netherlands, Germany, Australia, Ireland) has created a new type of organic material that learns from its past behavior emulating synaptic behavior. The molecule switches from high to low conductance states with massive negative memristive behaviour that depends on the drive speed and number of past switching events. The dynamic molecular switch provides all the fundamental logic gates necessary for deep learning because of its time-domain and voltage-dependent plasticity. The switch represents an adaptable molecular-scale hardware operable in solid-state devices and opens a pathway […]

Researchers develop a material that mimics how the brain stores information

Nanowerk  November 8, 2022 While a precise modulation of magnetism is achieved when voltage is applied, much more uncontrolled is the spontaneous evolution of magneto-ionic systems upon removing the electric stimuli. An international team of researchers (Spain, Italy, Belgium) has demonstrated a voltage-controllable N ion accumulation effect at the outer surface of CoN films adjacent to a liquid electrolyte, which allows for the control of magneto-ionic properties both during and after voltage pulse actuation (i.e., stimulated, and post-stimulated behavior, respectively). This effect, which takes place when the CoN film thickness is below 50 nm and the voltage pulse frequency is […]