Ohm’s Law Survives to the Atomic Scale

Science ◽  
2012 ◽  
Vol 335 (6064) ◽  
pp. 64-67 ◽  
Author(s):  
B. Weber ◽  
S. Mahapatra ◽  
H. Ryu ◽  
S. Lee ◽  
A. Fuhrer ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Quantum Information Processing ◽  
Silicon Crystal ◽  
Tight Binding ◽  
Atomic Scale ◽  
Single Atom ◽  
Active Device ◽  
Average Spacing ◽  
Surfaces And Interfaces ◽  
Atomic Limit

As silicon electronics approaches the atomic scale, interconnects and circuitry become comparable in size to the active device components. Maintaining low electrical resistivity at this scale is challenging because of the presence of confining surfaces and interfaces. We report on the fabrication of wires in silicon—only one atom tall and four atoms wide—with exceptionally low resistivity (~0.3 milliohm-centimeters) and the current-carrying capabilities of copper. By embedding phosphorus atoms within a silicon crystal with an average spacing of less than 1 nanometer, we achieved a diameter-independent resistivity, which demonstrates ohmic scaling to the atomic limit. Atomistic tight-binding calculations confirm the metallicity of these atomic-scale wires, which pave the way for single-atom device architectures for both classical and quantum information processing.

scholarly journals Probing resonating valence bond states in artificial quantum magnets

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kai Yang ◽  
Soo-Hyon Phark ◽  
Yujeong Bae ◽  
Taner Esat ◽  
Philip Willke ◽  
...  
Keyword(s):  
Quantum Information Processing ◽  
Energy Levels ◽  
Finite Size ◽  
Valence Bond ◽  
Exchange Interactions ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Many Body ◽  
Quantum Magnets ◽  
Resonating Valence Bond

AbstractDesigning and characterizing the many-body behaviors of quantum materials represents a prominent challenge for understanding strongly correlated physics and quantum information processing. We constructed artificial quantum magnets on a surface by using spin-1/2 atoms in a scanning tunneling microscope (STM). These coupled spins feature strong quantum fluctuations due to antiferromagnetic exchange interactions between neighboring atoms. To characterize the resulting collective magnetic states and their energy levels, we performed electron spin resonance on individual atoms within each quantum magnet. This gives atomic-scale access to properties of the exotic quantum many-body states, such as a finite-size realization of a resonating valence bond state. The tunable atomic-scale magnetic field from the STM tip allows us to further characterize and engineer the quantum states. These results open a new avenue to designing and exploring quantum magnets at the atomic scale for applications in spintronics and quantum simulations.

scholarly journals Site-Specific Electrodeposition Enables Self-Terminating Growth of Atomically Dispersed Metal Catalysts

2020 ◽  
Author(s):  
Yi Shi ◽  
Wenmao Huang ◽  
Jian Li ◽  
Yue Zhou ◽  
Zhongqiu Li ◽  
...  
Keyword(s):  
Large Scale ◽  
Transition Metal Dichalcogenides ◽  
Metal Catalysts ◽  
Atomic Scale ◽  
Single Atom ◽  
Scale Production ◽  
Heterogenous Catalysis ◽  
Site Specific ◽  
Metal Support ◽  
Metal Dichalcogenides

<p>The growth of atomically dispersed metal catalysts (ADMCs) remains a great challenge owing to the thermodynamically driven atom aggregation. Here we report a surface-limited electrodeposition technique that uses site-specific substrates for the rapid and room-temperature synthesis of ADMCs. We obtained ADMCs by the underpotential deposition (UPD) of a single-atom nonnoble metal onto the chalcogen atoms of chemically exfoliated transition metal dichalcogenides and subsequent galvanic displacement with a more-noble single-atom metal. The site-specific electrodeposition (SSED) enables the formation of energetically favorable metal–support bonds, and then automatically terminates the sequential formation of metallic bonding. The self-terminating effect restricts the metal deposition to the atomic scale. The modulated ADMCs exhibit remarkable activity and stability in the hydrogen evolution reaction compared to state-of-the-art single-atom electrocatalysts. We demonstrate that this SSED methodology could be extended to the synthesis of a variety of ADMCs (for example, Pt, Pd, Rh, Cu, Pb, Bi, and Sn single atoms), showing its general scope for the large-scale production of functional ADMCs in heterogenous catalysis. </p>

scholarly journals Site-Specific Electrodeposition Enables Self-Terminating Growth of Atomically Dispersed Metal Catalysts

2020 ◽  
Author(s):  
Yi Shi ◽  
Wenmao Huang ◽  
Jian Li ◽  
Yue Zhou ◽  
Zhongqiu Li ◽  
...  
Keyword(s):  
Large Scale ◽  
Transition Metal Dichalcogenides ◽  
Metal Catalysts ◽  
Atomic Scale ◽  
Single Atom ◽  
Scale Production ◽  
Heterogenous Catalysis ◽  
Site Specific ◽  
Metal Support ◽  
Metal Dichalcogenides

<p>The growth of atomically dispersed metal catalysts (ADMCs) remains a great challenge owing to the thermodynamically driven atom aggregation. Here we report a surface-limited electrodeposition technique that uses site-specific substrates for the rapid and room-temperature synthesis of ADMCs. We obtained ADMCs by the underpotential deposition (UPD) of a single-atom nonnoble metal onto the chalcogen atoms of chemically exfoliated transition metal dichalcogenides and subsequent galvanic displacement with a more-noble single-atom metal. The site-specific electrodeposition (SSED) enables the formation of energetically favorable metal–support bonds, and then automatically terminates the sequential formation of metallic bonding. The self-terminating effect restricts the metal deposition to the atomic scale. The modulated ADMCs exhibit remarkable activity and stability in the hydrogen evolution reaction compared to state-of-the-art single-atom electrocatalysts. We demonstrate that this SSED methodology could be extended to the synthesis of a variety of ADMCs (for example, Pt, Pd, Rh, Cu, Pb, Bi, and Sn single atoms), showing its general scope for the large-scale production of functional ADMCs in heterogenous catalysis. </p>

Study of electron-phonon coupling and its effect on electrical resistivity in HF systems

2019 ◽  
Vol 33 (04) ◽  
pp. 1950012
Author(s):  
P. C. Baral
Keyword(s):  
Electrical Resistivity ◽  
Mean Field Theory ◽  
Tight Binding ◽  
Harmonic Approximation ◽  
Mean Field ◽  
Graphical Analysis ◽  
Kondo Lattice ◽  
Model Parameters ◽  
Binding Model ◽  
Model Hamiltonian

In this work, we report on theoretical study of the effect of electron-phonon (EP) interaction in THz frequency and temperature dependence of the electrical resistivity in heavy fermion (HF) systems. For this purpose, a model Hamiltonian is considered which consists of the Heisenberg type exchange interaction between localized moments and a tight binding model called the Kondo lattice model (KLM). The effect of EP coupling on electrical resistivity is presented by considering phonon interaction to bare f-electrons, band electrons and to the hybridization between band and f-electrons as a perturbed term. The phonon Hamiltonian in harmonic approximation is also included. The model Hamiltonian is solved by employing the mean-field theory (MFT) along with the Hubbard model of approximation. The temperature- and frequency-dependent electrical resistivity exhibits change in slopes at T[Formula: see text] as well as at T[Formula: see text]. The theoretical findings from the graphical analysis by varying the model parameters g[Formula: see text], g[Formula: see text] and g[Formula: see text] are compared to some of the experimental results in HF systems.

scholarly journals Single-atom vibrational spectroscopy in the scanning transmission electron microscope

Science ◽  
2020 ◽  
Vol 367 (6482) ◽  
pp. 1124-1127 ◽  
Author(s):  
F. S. Hage ◽  
G. Radtke ◽  
D. M. Kepaptsoglou ◽  
M. Lazzeri ◽  
Q. M. Ramasse
Keyword(s):  
Electron Microscope ◽  
Vibrational Spectroscopy ◽  
Materials Science ◽  
Scanning Transmission Electron Microscope ◽  
Atomic Scale ◽  
Single Atom ◽  
Phonon Modes ◽  
Resonant States ◽  
Resolution Electron ◽  
Scanning Transmission

Single-atom impurities and other atomic-scale defects can notably alter the local vibrational responses of solids and, ultimately, their macroscopic properties. Using high-resolution electron energy-loss spectroscopy in the electron microscope, we show that a single substitutional silicon impurity in graphene induces a characteristic, localized modification of the vibrational response. Extensive ab initio calculations reveal that the measured spectroscopic signature arises from defect-induced pseudo-localized phonon modes—that is, resonant states resulting from the hybridization of the defect modes and the bulk continuum—with energies that can be directly matched to the experiments. This finding realizes the promise of vibrational spectroscopy in the electron microscope with single-atom sensitivity and has broad implications across the fields of physics, chemistry, and materials science.

Quantitative Annular Dark Field Electron Microscopy Using Single Electron Signals

2013 ◽  
Vol 20 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Ryo Ishikawa ◽  
Andrew R. Lupini ◽  
Scott D. Findlay ◽  
Stephen J. Pennycook
Keyword(s):  
Electron Microscopy ◽  
Dynamic Range ◽  
Light Element ◽  
Dark Field ◽  
Atomic Scale ◽  
Single Electron ◽  
Single Atom ◽  
Intensity Level ◽  
Primitive Cell ◽  
Annular Dark Field

AbstractOne of the difficulties in analyzing atomic resolution electron microscope images is that the sample thickness is usually unknown or has to be fitted from parameters that are not precisely known. An accurate measure of thickness, ideally on a column-by-column basis, parameter free, and with single atom accuracy, would be of great value for many applications, such as matching to simulations. Here we propose such a quantification method for annular dark field scanning transmission electron microscopy by using the single electron intensity level of the detector. This method has the advantage that we can routinely quantify annular dark field images operating at both low and high beam currents, and under high dynamic range conditions, which is useful for the quantification of ultra-thin or light-element materials. To facilitate atom counting at the atomic scale we use the mean intensity in an annular dark field image averaged over a primitive cell, with no free parameters to be fitted. To illustrate the potential of our method, we demonstrate counting the number of Al (or N) atoms in a wurtzite-type aluminum nitride single crystal at each primitive cell over the range of 3–99 atoms.

scholarly journals Site-specific electrodeposition enables self-terminating growth of atomically dispersed metal catalysts

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yi Shi ◽  
Wen-Mao Huang ◽  
Jian Li ◽  
Yue Zhou ◽  
Zhong-Qiu Li ◽  
...  
Keyword(s):  
Transition Metal Dichalcogenides ◽  
Metal Catalysts ◽  
Atomic Scale ◽  
Single Atom ◽  
Site Specific ◽  
Metal Support ◽  
Metal Dichalcogenides ◽  
Metallic Bonding ◽  
General Scope ◽  
Sequential Formation

Abstract The growth of atomically dispersed metal catalysts (ADMCs) remains a great challenge owing to the thermodynamically driven atom aggregation. Here we report a surface-limited electrodeposition technique that uses site-specific substrates for the rapid and room-temperature synthesis of ADMCs. We obtained ADMCs by the underpotential deposition of a non-noble single-atom metal onto the chalcogen atoms of transition metal dichalcogenides and subsequent galvanic displacement with a more-noble single-atom metal. The site-specific electrodeposition enables the formation of energetically favorable metal–support bonds, and then automatically terminates the sequential formation of metallic bonding. The self-terminating effect restricts the metal deposition to the atomic scale. The modulated ADMCs exhibit remarkable activity and stability in the hydrogen evolution reaction compared to state-of-the-art single-atom electrocatalysts. We demonstrate that this methodology could be extended to the synthesis of a variety of ADMCs (Pt, Pd, Rh, Cu, Pb, Bi, and Sn), showing its general scope for functional ADMCs manufacturing in heterogeneous catalysis.

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