Lifeboat Foundation

Beijing researchers made a pseudo-CMOS architecture for sub-picowatt logic computing that uses self-biased molybdenum disulfide transistors.

As transistors are scaled to smaller dimensions, their static power increases. Combining two-dimensional (2D) channel materials with complementary metal–oxide–semiconductor (CMOS) logic architectures could be an effective solution to this issue because of the excellent field-effect properties of 2D materials. However, 2D materials have limited polarity control. The transistors have a gapped channel that forms a tunable barrier—thus circumventing the polarity control of 2D materials—and exhibit a reverse-saturation current below 1 pA with high reliability and endurance.

They use the devices to make homojunction-loaded inverters with good rail-to-rail operation at a switching threshold voltage of around 0.5 V, a static power of a few picowatts, a dynamic delay time of around 200 µs, a noise margin of more than 90% and a peak voltage gain of 241. They also fabricate fundamental gate circuits on the basis of this pseudo-CMOS configuration by cascading several devices.

RuO2 has been established as the benchmark catalyst for the oxygen evolution reaction (OER). However, the low precious metal content compared to other OER industrial catalysts like RuO2, Pt/C, and IrO2 makes a hybrid heterosurface of RuO2 and F-doped graphene (RuO2@FGr) an excellent catalyst with a high current density. Moreover, the advantage of graphene support increases stability. We investigated the mechanism of the OER on RuO2@FGr using density functional theory (DFT) and the computational hydrogen electrode model (CHEM). In CHEM, the adsorption energy of the reactive intermediates is considered for the reduction potential calculation. This is followed by free energy calculation and, eventually, overpotential calculation using standard or reversible hydrogen electrodes (SHE/RHE). Computational OER activity calculated in the gas phase using density functional theory (DFT) cannot explain the contribution of the condensed phase, water organization energy, the kinetics of the elementary steps, and electrochemical contribution. The current study will address the issue by implementing an implicit solvation model and the electrostatic contribution by considering the charge extrapolation model. We used molecular RuO2 to mimic the exact experimental weight percentage. Fluorine intercalation doping improves the binding of oxygen-based intermediate species to the reactive surface due to a shift in the d-band center toward the Fermi level. The graphene sheet behaves as a conductor after fluorine doping, and the electron density contribution near the Fermi level is clearly distinguished from the projected density of states (PDOS). Using the implicit solvation model with altered parameters, we find improvements in the reaction barrier for hydroperoxo formation. An overpotential of 0.40 V vs RHE is obtained for the cavity shape parameter and charge density cutoff parameter of 0.8 and 0.0035 Å–3. For completion, we implement the constant potential model (CPM) to extrapolate our results calculated at the nonzero potential environment to 0.0 V potential. The mean energy path computed using the climbing image nudged elastic band provides the activation and reaction energy, and the values are extrapolated to 0.0 V RHE using the CPM correction. Implementing both thermochemical and electrochemical corrections simultaneously, we can find a reasonable overpotential of the studied catalytic reaction.

Relying on sub-wavelength nanostructures, metasurfaces have been shown as promising candidates for replacing conventional free-space optical components by arbitrarily manipulating the amplitude, phase, and polarization of optical wavefronts in certain applications^1,2,3. In recent years, the scope of their applications has been expanded towards complete spatio-temporal control through the introduction of active metasurfaces. These developments open up exciting new possibilities for dynamic holography⁴, faster spatial light modulators⁵, and fast optical beam steering for LiDAR⁶. Large efforts have been channeled into various modulation mechanisms⁷. Microelectromechanical and nanoelectromechanical systems (MEMS and NEMS)^8,9,10,11 have the advantages of low-cost and CMOS-compatibility, but the speed is limited up to MHz. Phase-change materials^12,13,14 have fast, drastic, and non-volatile refractive index change, but lack continuous refractive index tuning and have a limited number of cycles constraining applicability to reconfigurable devices. Through molecule reorientation, liquid crystal can have index modulation over 10%, while under relatively low applied voltages Tunable liquid crystal metasurfaces, U.S. patent number 10,665,953 [Application Number 16/505,687]¹⁵. Techniques of liquid crystal integration have also advanced after decades of development. However, the tuning speeds are limited to kHz range¹⁶. Thermal-optic effects can induce relatively large refractive index changes^17,18, but the speed is inherently limited and the on-chip thermal management can be challenging. The co-integration of transparent conductive oxide and metallic plasmonic structures^5,6 has been demonstrated in epsilon-near-zero (ENZ) regime to control the wavefront of reflected light, but the low reflection amplitude induced by the optical loss of the materials and the ENZ regime is unavoidable.

In modern photonics, a multitude of technologies for tunable optics and frequency conversion^19,20 are realized with nonlinear materials that have low loss and a strong χ effect, such as lithium niobate^21,22, aluminum nitride²³, and organic electro-optic (OEO) materials²⁴. Their ultrafast responses make it possible to use RF or millimeter-wave control²⁵. Developments in computational chemistry have also led to artificially engineered organic molecules that have record-high nonlinear coefficients with long-term and high-temperature stability^26,27. However, their potential in modifying free-space light has been relatively unexplored until recently. Several OEO material-hybrid designs have demonstrated improved tunability of metasurfaces^28,29,30. Utilizing dielectric resonant structures and RF-compatible coplanar waveguides, a free-space silicon-organic modulator has recently accomplished GHz modulation speed³¹. However, all demonstrations to date require high operating voltages ± 60V, due to low resonance tuning capability (frequency shift / voltage), which hinders their integration with electronic chips.

In this work, we propose combining high-Q metasurfaces based on slot-mode resonances with the unique nano-fabrication techniques enabled by OEO materials, which drastically reduces the operating voltage. The low voltage is mainly achieved from the ability to place the electrodes in close proximity to each other while hosting high-Q modes in between and the large overlap of the optical and RF fields in OEO materials. In the following sections, we first provide the design concepts and considerations for achieving a reduced operating voltage. Next, we numerically demonstrate the advantage of a particular selected mode compared to other supported modes in the structure. Finally, we experimentally realize our concepts and characterize the performance of the electro-optic metasurface.

Musk said that the first human patient implanted with a Neuralink chip last month “is able to… move the mouse around the screen just by thinking.”

How Does The Neutral Atom Approach Compare

The neutral atom approach is a well-known and extensively investigated approach to quantum computing. The approach offers numerous advantages, especially in terms of scalability, expense, error mitigation, error correction, coherence, and simplicity.

Neutral atom quantum computing utilizes individual atoms, typically alkali atoms like rubidium or cesium, suspended and isolated in a vacuum and manipulated using precisely targeted laser beams. These atoms are not ionized, meaning they retain all their electrons and do not carry an electric charge, which distinguishes them from trapped ion approaches. The quantum states of these neutral atoms, such as their energy levels or the orientation of their spins, serve as the basis for qubits. By employing optical tweezers—focused laser beams that trap and hold the atoms in place—arrays of atoms can be arranged in customizable patterns, allowing for the encoding and manipulation of quantum information.

Elon Musk announced this week that his company’s brain implant has allowed a person to move a computer mouse with their mind.

Relying on sub-wavelength nanostructures, metasurfaces have been shown as promising candidates for replacing conventional free-space optical components by arbitrarily manipulating the amplitude, phase, and polarization of optical wavefronts in certain applications^1,2,3. In recent years, the scope of their applications has been expanded towards complete spatio-temporal control through the introduction of active metasurfaces. These developments open up exciting new possibilities for dynamic holography⁴, faster spatial light modulators⁵, and fast optical beam steering for LiDAR⁶. Large efforts have been channeled into various modulation mechanisms⁷. Microelectromechanical and nanoelectromechanical systems (MEMS and NEMS)^8,9,10,11 have the advantages of low-cost and CMOS-compatibility, but the speed is limited up to MHz. Phase-change materials^12,13,14 have fast, drastic, and non-volatile refractive index change, but lack continuous refractive index tuning and have a limited number of cycles constraining applicability to reconfigurable devices. Through molecule reorientation, liquid crystal can have index modulation over 10%, while under relatively low applied voltages Tunable liquid crystal metasurfaces, U.S. patent number 10,665,953 [Application Number 16/505,687]¹⁵. Techniques of liquid crystal integration have also advanced after decades of development. However, the tuning speeds are limited to kHz range¹⁶. Thermal-optic effects can induce relatively large refractive index changes^17,18, but the speed is inherently limited and the on-chip thermal management can be challenging. The co-integration of transparent conductive oxide and metallic plasmonic structures^5,6 has been demonstrated in epsilon-near-zero (ENZ) regime to control the wavefront of reflected light, but the low reflection amplitude induced by the optical loss of the materials and the ENZ regime is unavoidable.

In modern photonics, a multitude of technologies for tunable optics and frequency conversion^19,20 are realized with nonlinear materials that have low loss and a strong χ effect, such as lithium niobate^21,22, aluminum nitride²³, and organic electro-optic (OEO) materials²⁴. Their ultrafast responses make it possible to use RF or millimeter-wave control²⁵. Developments in computational chemistry have also led to artificially engineered organic molecules that have record-high nonlinear coefficients with long-term and high-temperature stability^26,27. However, their potential in modifying free-space light has been relatively unexplored until recently. Several OEO material-hybrid designs have demonstrated improved tunability of metasurfaces^28,29,30. Utilizing dielectric resonant structures and RF-compatible coplanar waveguides, a free-space silicon-organic modulator has recently accomplished GHz modulation speed³¹. However, all demonstrations to date require high operating voltages ± 60V, due to low resonance tuning capability (frequency shift / voltage), which hinders their integration with electronic chips.

In this work, we propose combining high-Q metasurfaces based on slot-mode resonances with the unique nano-fabrication techniques enabled by OEO materials, which drastically reduces the operating voltage. The low voltage is mainly achieved from the ability to place the electrodes in close proximity to each other while hosting high-Q modes in between and the large overlap of the optical and RF fields in OEO materials. In the following sections, we first provide the design concepts and considerations for achieving a reduced operating voltage. Next, we numerically demonstrate the advantage of a particular selected mode compared to other supported modes in the structure. Finally, we experimentally realize our concepts and characterize the performance of the electro-optic metasurface.

MIT researchers used ultrathin van der Waals materials to create an electron magnet that can be switched at room temperature. This type of magnet could be used to build magnetic processors or memories that would consume far less energy than silicon devices.

The Quantum Insider (TQI) is the leading online resource dedicated exclusively to Quantum Computing.