Room-temperature control and electrical readout of individual nitrogen-vacancy nuclear spins

Nuclear spins in semiconductors are leading candidates for future quantum technologies, including quantum computation, communication, and sensing. Nuclear spins in diamond are particularly attractive due to their long coherence time. With the nitrogen-vacancy (NV) centre, such nuclear qubits benefit from an auxiliary electronic qubit, which, at cryogenic temperatures, enables probabilistic entanglement mediated optically by photonic links. Here, we demonstrate a concept of a microelectronic quantum device at ambient conditions using diamond as wide bandgap semiconductor. The basic quantum processor unit – a single 14N nuclear spin coupled to the NV electron – is read photoelectrically and thus operates in a manner compatible with nanoscale electronics. The underlying theory provides the key ingredients for photoelectric quantum gate operations and readout of nuclear qubit registers. This demonstration is, therefore, a step towards diamond quantum devices with a readout area limited by inter-electrode distance rather than by the diffraction limit. Such scalability could enable the development of electronic quantum processors based on the dipolar interaction of spin-qubits placed at nanoscopic proximity.

One-dimensional van der Waals stacked p-type crystal Ta2Pt3Se8 for nanoscale electronics

Recently, ternary transition metal chalcogenide Ta2X3Se8 (X = Pd or Pt) has attracted great interest as a class of emerging one-dimensional (1D) van der Waals (vdW) materials. In particular,Ta2Pd3Se8 has...

Towards a First-Principles Evaluation of Transport Mechanisms in Molecular Wires

Understanding charge transport through molecular wires is important for nanoscale electronics and biochemistry. Our goal is to establish a simple first-principles protocol for predicting the charge transport mechanism in such wires, in particular the crossover from coherent tunneling for short wires to incoherent hopping for longer wires. This protocol is based on a combination of density-functional theory with a polarizable continuum model introduced by Kaupp et al. for mixed-valence molecules, which we had previously found to work well for length-dependent charge delocalization in such systems. We combine this protocol with a new charge delocalization measure tailored for molecular wires, and we show that it can predict the tunneling-to hopping transition length with a maximum error of one subunit in five sets of molecular wires studied experimentally in molecular junctions at room temperature. This suggests that the protocol is also well suited for estimating the extent of hopping sites as relevant, e.g., for the intermediate tunneling-hopping regime in DNA.

Towards a First-Principles Evaluation of Transport Mechanisms in Molecular Wires

Understanding charge transport through molecular wires is important for nanoscale electronics and biochemistry. Our goal is to establish a simple first-principles protocol for predicting the charge transport mechanism in such wires, in particular the crossover from coherent tunneling for short wires to incoherent hopping for longer wires. This protocol is based on a combination of density-functional theory with a polarizable continuum model introduced by Kaupp et al. for mixed-valence molecules, which we had previously found to work well for length-dependent charge delocalization in such systems. We combine this protocol with a new charge delocalization measure tailored for molecular wires, and we show that it can predict the tunneling-to hopping transition length with a maximum error of one subunit in five sets of molecular wires studied experimentally in molecular junctions at room temperature. This suggests that the protocol is also well suited for estimating the extent of hopping sites as relevant, e.g., for the intermediate tunneling-hopping regime in DNA.

In the Matter of United States v. Charles M. Lieber: A Scientific Misconduct or Political Paranoia Case.

Charles M. Lieber, a prominent scientist, a leader in his field of nanoscale electronics, and the Chairman of the Department of Chemistry and Chemical Biology at a pre-eminent tertiary institution, Harvard University was arrested on January 28, 2020 by the F.B.I. and will be prosecuted by the United States Attorney for the District of Massachusetts for the alleged crime of making false statements to the National Institutes of Health and the United States Government, and not declaring various monetary income with respect to his association with the Wuhan University of Technology and the China's Thousand Talents Program. Is this a Scientific Misconduct case or just plain political paranoia.

Charge transport and energy storage at the molecular scale: from nanoelectronics to electrochemical sensing

This tutorial review considers how the fundamental quantized properties associated with charge transport and storage, particularly in molecular films, are linked in a manner that spans nanoscale electronics, electrochemistry, redox switching, and derived nanoscale sensing.

Native Point Defect Measurement and Manipulation in ZnO Nanostructures

This review presents recent research advances in measuring native point defects in ZnO nanostructures, establishing how these defects affect nanoscale electronic properties, and developing new techniques to manipulate these defects to control nano- and micro- wire electronic properties. From spatially-resolved cathodoluminescence spectroscopy, we now know that electrically-active native point defects are present inside, as well as at the surfaces of, ZnO and other semiconductor nanostructures. These defects within nanowires and at their metal interfaces can dominate electrical contact properties, yet they are sensitive to manipulation by chemical interactions, energy beams, as well as applied electrical fields. Non-uniform defect distributions are common among semiconductors, and their effects are magnified in semiconductor nanostructures so that their electronic effects are significant. The ability to measure native point defects directly on a nanoscale and manipulate their spatial distributions by multiple techniques presents exciting possibilities for future ZnO nanoscale electronics.

Self-Crossing Memristive Pinched Hystereses in Autonomous Implicit Models

This paper shows that autonomous implicit ODEs (based on planar lemniscates) are interesting models, yielding pinched self-crossing hystereses that are intrinsic features of all memristive elements in nanoscale electronics. Each model has a folded saddle that allows for an oscillating trajectory to traverse different sides of singularity. The models considered in this paper are autonomous and therefore different from typical input–state–output models considered thus far. The models preserve the usual properties of memristive elements. For example, the area enclosed by the pinched hystereses decreases with the increased frequency of oscillations. The same-time instant zero-crossing property is also satisfied provided that certain conditions are met. Another novel aspect of this paper is the fact that the autonomous models are based on various planar lemniscates (of Gerono, Devil and Bernoulli) which can be nonlinearly transformed to model pinched hystereses of various shapes. The proposed models are differentiable and the use of the sign and absolute value terms, typical in modeling of memristive elements, is avoided. Several simulation results are included and two simple analog circuits having the pinched hysteretic characteristics of mem-inductors and mem-capacitors are proposed.