Makusu Tsutsui

The self-breaking mechanism of gold junctions is studied by investigating stability of the atom-sized contacts. The single atom contact lifetime increases from about 0.02 to 200 s upon decreasing the junction stretching speed, while at the same time, the breaking force diminishes logarithmically. We find that the junction self-breaking processes involve sufficient atomic rearrangements, which thereby allow complete self-compensation of externally introduced strain at 0.8 pm/s. The present result

Abstract Ion transport and hydrodynamic flow through nanometer-sized channels (nanopores) have been increasingly studied owing to not only the fundamental interest in the abundance of novel phenomena that has been observed but also their promising application in innovative nanodevices, including next-generation sequencers, nanopower generators, and memristive synapses. We first review various kinds of materials and the associated state-of-the-art processes developed for fabricating nanoscale por

We report a technique that can be utilized as a nanoscale thermometer and its application to metal-molecule-metal junctions at room temperatures. We find that a molecular junction heats up to 463 K at 1 V. We also revealed an onset bias of approximately 0.04 V for heat generation via electron-phonon scattering by examining inelastic electron tunneling spectroscopy. The present results suggest the importance of attaining an optimal thermal link at molecule-electrode interfaces for providing pract

We explored single-particle translocation through a low thickness-to-diameter aspect ratio Si(3)N(4) pore mimicking graphene nanopore structure by a resistive pulse method. Ionic conductance of 0.05 aspect ratio pores scales linearly with the diameter, indicating predominant contribution of the access resistance to the ion transport. We find that the access resistance changes little during particle translocation. Furthermore, we observe enhanced particle capture rates via the strong electric fie

Conductance of single 1,4-benzenedithiol (BDT) molecules is investigated in a wide range (0–0.3)G0, exploiting mechanically controllable break junction technique. The authors observed a series of clear conductance steps both in low- (∼0.01G0) and high-conductance (∼0.1G0) regimes and corresponding two sets of peak structures in the conductance histograms. The two distinct conductance states are attributable to different Au–S bonding configurations of Au∕BDT∕Au junctions. The high-bias measuremen

Electrode-embedded nanopore is considered as a promising device structure for label-free single-molecule sequencing, the principle of which is based on nucleotide identification via transverse electron tunnelling current flowing through a DNA translocating through the pore. Yet, fabrication of a molecular-scale electrode-nanopore detector has been a formidable task that requires atomic-level alignment of a few nanometer sized pore and an electrode gap. Here, we report single-molecule detection u

We report label-free electrical detections of chemically modified nucleobases in a DNA using a nucleotide-sized electrode gap. We found that methyl substitution contributes to increase the tunneling conductance of deoxycytidines, which was attributed to a shift of the highest occupied molecular orbital level closer to the electrode Fermi level by methylation. We also demonstrate statistical identifications of methylcytosines in an oligonucleotide by tunneling current. This result suggests a poss

Conventional concepts of resistive pulse analysis is to discriminate particles in liquid by the difference in their size through comparing the amount of ionic current blockage. In sharp contrast, we herein report a proof-of-concept demonstration of the shape sensing capability of solid-state pore sensors by leveraging the synergy between nanopore technology and machine learning. We found ionic current spikes of similar patterns for two bacteria reflecting the closely resembled morphology and siz

Resistive pulse sensing with nanopores having a low thickness-to-diameter aspect-ratio structure is expected to enable high-spatial-resolution analysis of nanoscale objects in a liquid. Here we investigated the sensing capability of low-aspect-ratio pore sensors by monitoring the ionic current blockades during translocation of polymeric nanobeads. We detected numerous small current spikes due to partial occlusion of the pore orifice by particles diffusing therein reflecting the expansive electri

Nanopore analysis is an emerging single-molecule strategy for non-optical and high-throughput DNA sequencing, the principle of which is based on identification of each constituent nucleobase by measuring trans-membrane ionic current blockade or transverse tunnelling current as it moves through the pore. A crucial issue for nanopore sequencing is the fact that DNA translocates a nanopore too fast for addressing sequence with a single base resolution. Here we report that a transverse electric fiel

Practical realization of any electronic device requires a quantitative measure of their durability for the sake of guaranteeing the reliability. Unfortunately, however, there exists no such tool for molecular devices. The present article provides a solution to this issue in molecular electronics by reporting an experimental demonstration of a quantitative comparison of thermodynamic stability of single-molecule junctions consisting of two distinct anchor groups: thiol and amine. We report solid

Label-free and real-time single-molecule detection may aid the development of high-throughput biosensing platforms. Molecular fluctuations are a source of noise that often hinders single-molecule identification by obscuring the fine details of molecular identity. In this study, we report molecular identification through direct observation of quantum-fluctuation-induced inelastic noise in single organic molecules. We investigated current fluctuations flowing through a single molecule that is chem

Metal-molecule-metal junction is a promising candidate for thermoelectric applications that utilizes quantum confinement effects in the chemically defined zero-dimensional atomic structure to achieve enhanced dimensionless figure of merit ZT. A key issue in this new class of thermoelectric nanomaterials is to clarify the sensitivity of thermoelectricity on the molecular junction configurations. Here we report simultaneous measurements of the thermoelectric voltage and conductance on Au-1,4-benze