Friction is responsible for about one-third of the primary energy consumption in world. So far, a thorough atomistic understanding frictional dissipation mechanisms still lacking. The Amontons' law states that kinetic friction independent sliding velocity while Prandtl-Tomlinson model suggests damping proportional to relative between two contacting objects. Through careful analysis process atomic force microscopy measurements, here we propose tip oscillation speed induced by friction. It...

Friction represents a major energy dissipation mode, yet the atomistic mechanism of how friction converts mechanical motion into heat remains elusive. It has been suggested that excess phonons are mainly excited at washboard frequency, fundamental frequency which relative excites interface atoms, and subsequent thermalization these nonequilibrium completes process. Through combined atomic force microscopy measurements modeling, here we show nonlinear interactions between sliding tip...

Friction force microscopy experiments on moiré superstructures of graphene-coated platinum surfaces demonstrate that in addition to atomic stick-slip dynamics, a new dominant energy dissipation route emerges. The underlying mechanism, revealed by atomistic molecular dynamics simulations, is related ridge elastic deformations and subsequent relaxation due the action pushing tip. measured frictional velocity dependence displays two distinct regimes: (i) at low velocities, friction small nearly...

The fine control of molecules or atoms in self-assemblies on surfaces is a great challenge for future nanodevices, specially unidimensional structure formations. In this context, our study explores the adsorption behavior benzo-fused double [7]thiahelicene (DT7H) Cu(111). Using non-contact atomic force microscopy (nc-AFM) at room temperature, we prove their capability construction linear-like shape adlayers. After gentle annealing DT7H-copper interface, are prone to form non-covalent...

Abstract A comprehensive study of monolayer MoS 2 on a single‐crystal Au(111) surface is reported, combining ultra‐high vacuum scanning probe microscopy with advanced computational methods. Kelvin force precisely quantified the work function heterointerface, while topographic analysis by contact and non‐contact atomic revealed moiré superlattice an interfacial twist angle 0.45° between Au(111). To accurately model predict out‐of‐plane corrugation these superlattices, semi‐anisotropic...

The moiré superlattice in twisted van der Waals heterostructures is of central importance for the modulation electronic and optical properties system, yet mechanical dissipation such systems remains largely unexplored. Here, we report experimental observations energy across both vertical lateral directions along superstructures, revealing a significant increase at ridges compared to flat domains. Comparison measurements with theoretical phononic model suggests that local originates from...

The structural and superlubric properties of single layer MoS2 on Au(1 1 1) forming moiré superlattice structures have been investigated by means ultrahigh vacuum atomic force microscope with bimodal contact modes. We synthesize epitaxial monolayer flakes the surface in vacuum. Using friction microscopy, measurements indicate a regime between tip apex corrugated which remains at an ultralow value is independent from normal load. Superlubricity conditions are observed for different loads...

The transition from single to multiple atomic slips, theoretically expected and important in atomic-scale friction, has never been demonstrated experimentally as a function of velocity. Here we show by high-resolution friction force microscopy on monolayer MoS_{2}/Au(111) that slips leave unique footprint-a frictional velocity weakening. Specifically, wide interval 10 100 nm/s, surprisingly decreases. Model simulations similar nonmonotonic behavior at velocities quantitative agreement with...

The track regularity of a permanent-magnet guideway (PMG) is an important issue to ensure the riding comfort and running stability high-temperature superconducting (HTS) maglev vehicles. Compared with defects typical railway tracks, similar on PMG could affect magnetic field at levitation height then influence performance system. In this paper, four kinds Halbach distribution was investigated by finite-element simulation method. According calculation results, it found that sensitivity...

Abstract Atomistic mechanisms of frictional energy dissipation have attracted significant attention. However, the dynamics phonon excitation and remain elusive for many friction processes. Through systematic fast Fourier transform analyses signals as a silicon tip sliding over graphite surface at different angles velocities, we experimentally demonstrate that mainly excites non-equilibrium phonons washboard frequency its harmonics. Using molecular simulations, further disclose phononic...

The afterglow intensity and duration of ZnGa 2 O 4 :Cr 3+ are enhanced by regulating its trap distribution through doping lanthanide (Ln = Sm, Yb, Tb) ions guided the VRBE diagram. enhancement mechanism is analyzed in detail.

Abstract Despite significant progress in the fabrication and application of semiconductor materials for optical emitters sensors, few can cover cyan-gap between 450 500 nm. We here introduce a robust facile method to deposit amorphous Sb 2 S 3 films with bandgap 2.8 eV. By exploiting tunable functionality graphene, two-dimensional material, efficient deposition from chemical was achieved. Ozone-generated defects graphene were shown be required enhance morphology quality material...

A hybrid maglev model combining permanent magnet levitation (PML) and superconducting magnetic (SML) was designed fabricated to explore a heavy-load system advancing in passive stability simple structure. In this system, the PML levitate load, SML introduced guarantee stability. order realize different working gaps of two components, linear bearings were applied connect layer (for load) stability) model. Experimental results indicate that possesses excellent advantages ability at same time....

Against conventional wisdom, corrugated grain boundaries in polycrystalline graphene, grown on Pt(111) surfaces, are shown to exhibit negative friction coefficients and non-monotonic velocity dependence. Using combined experimental, simulation, modeling efforts, the underlying energy dissipation mechanism is found be dominated by dynamic buckling of boundary dislocation protrusions. The revealed expected appear a wide range two-dimensional material interfaces, thus supporting design...

Optimizing the efficiency of heat dissipation across an interface is a great challenge with continuously increasing integration microelectronic devices. In this work, effective method in tuning conduction Al/graphene/SiO2 reported. It was found that interfacial thermal conductance Al/irradiated graphene/SiO2 can be increased by factor 3, as compared Al/pristine graphene/SiO2. The X-ray photoelectron spectroscopy (XPS) analysis indicates ion irradiation may promote formation CO bonds on...

<title>Abstract</title> Against conventional wisdom, corrugated grain boundaries in polycrystalline graphene, grown on Pt(111) surfaces, are shown to exhibit negative friction coefficients and non-monotonic velocity dependence. Using combined experimental, simulation, modeling efforts, the underlying energy dissipation mechanism is found be dominated by dynamic buckling of boundary dislocation protrusions. The revealed expected appear a wide range two-dimensional material interfaces, thus...

Traditionally, friction force has been the benchmark for quantifying energy dissipation in frictional phenomena. In this study, we introduce an atomic chain model that illuminates conversion of kinetic into potential through interfacial forces. The process is characterized by release partial form phonons, quantifiable a damping coefficient. We have determined coefficient significantly influenced intrinsic dynamic properties system. Expanding on foundation, formulated advanced phononic...

Low thermal conductance (G) across metal/graphene interfaces presents an enormous challenge for the heat dissipation in graphene-based devices. In this paper, conduction Al/graphene/SiO2 interface at different doses of gallium (Ga) ion bombardment are explored. It is found that G gradually rises with increasing dose until a peak value obtained 6.88 × 1012 ions/cm2. The maximum enhancement Al/ion-bombarded graphene/SiO2 measured to be almost 6 times as much Al/pristine interface. Such large...