Electron Tunneling in Small-Area Junctions

2003 ◽  
Vol 17 (13n14) ◽  
pp. 763-769
Author(s):  
Alexander I. Khachaturov
Keyword(s):  
Bias Voltage ◽  
Wave Vector ◽  
Small Area ◽  
Electron Tunneling ◽  
Resonance Structure ◽  
Tunneling Conductance ◽  
Second Derivative ◽  
Tunnel Current ◽  
Lateral Wave ◽  
Wave Vector Component

Electron tunneling in small-area junctions has been treated. It is found that at the appropriate set of barrier parameters and electronic characteristics of the electrodes, the quantization of the lateral wave vector component manifests itself in the differential tunneling conductance as quite noticeable singularities. The dependance of the second derivative of the tunnel current versus the bias voltage calculated for the perfectly smooth quantized electrode should contain distinct periodic dips. It is shown that for real not perfectly smooth electrodes the resonance structure caused by the commensurate states may be observed.

ELECTRONICS OF MOLECULAR NANOCLUSTERS

2004 ◽  
Vol 03 (01n02) ◽  
pp. 137-147 ◽  
Author(s):  
V. V. KISLOV ◽  
Yu. V. GULYAEV ◽  
V. V. KOLESOV ◽  
I. V. TARANOV ◽  
S. P. GUBIN ◽  
...  
Keyword(s):  
Electron Tunneling ◽  
Langmuir Monolayers ◽  
Localized States ◽  
Nanocomposite Films ◽  
Molecular Cluster ◽  
Tunnel Current ◽  
Current Voltage ◽  
Single Electron Tunneling ◽  
Solid Substrates ◽  
Bottom To Top

The molecular nanoclusters proved to be very promising objects for applications in electronics not only because they have absolutely identical chemical structure and allow for bottom to top approach in constructing new electronic devices, but also for the possibility to design and create great variety of such clusters with specific properties. The formation and deposition of mixed Langmuir monolayers composed of inert amphiphile molecular matrix and guest ligand-stabilized metal-core nanoclusters are described. This approach allowed to obtain the ordered stable reproducible planar monolayer and multilayer nanocluster nanostructures on solid substrates. The use of novel polymeric Langmuir monolayers formed by amphiphilic polyelectrolytes and nanoclusters resulted in fabrication of ultimately thin monomolecular nanoscale-ordered stable planar polymeric nanocomposite films. The morphology and electron transport in fabricated nanostructures were studied experimentally using AFM and STM. The effects of single electron tunneling at room temperature through molecular cluster object containing finite number of localized states were theoretically investigated taking into account electron–electron Coulomb interaction. It is shown that tunnel current-bias voltage characteristic of such tunnel junction is characterized by a number of staircase steps equal to the number of cluster's eigenlevels, however the fronts of each steps are asymptotically linear with finite inclination. The analytically obtained current–voltage characteristics are in agreement with experimental results for electron tunneling through molecular nanoclusters at room temperatures.

scholarly journals Energy Loss in a MEMS Disk Resonator Gyroscope

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 493 ◽  
Author(s):  
Xie ◽  
Hao ◽  
Yuan
Keyword(s):  
Energy Loss ◽  
Bias Voltage ◽  
High Performance ◽  
Resonance Structure ◽  
Dissipated Energy ◽  
Thermoelastic Damping ◽  
Disk Resonator ◽  
Loss Mechanism ◽  
Energy Loss Mechanism ◽  
Anchor Loss

Analysing and minimizing energy loss is crucial for high performance disk resonator gyroscopes (DRGs). Generally, the primary energy loss mechanism for high vacuum packaged microelectromechanical system (MEMS) resonators includes thermoelastic damping, anchor loss, and electronic damping. In this paper, the thermoelastic damping, anchor loss, and electronic damping for our DRG design are calculated by combining finite element analysis and theoretical derivation. Thermoelastic damping is the dominant energy loss mechanism and contributes over 90% of the total dissipated energy. Benefiting from a symmetrical structure, the anchor loss is low and can be neglected. However, the electronic damping determined by the testing circuit contributes 2.6%–9.6% when the bias voltage increases from 10 V to 20 V, which has a considerable impact on the total quality factor (Q). For comparison, the gyroscope is fabricated and seal-packaged with a measured maximum Q range of 141k to 132k when the bias voltage varies. In conclusion, thermoelastic damping and electronic damping essentially determine the Q of the DRG. Thus, optimizing the resonance structure and testing the circuit to reduce energy loss is prioritized for a high-performance DRG design.

ELECTRON TUNNELING MEASUREMENTS OF ENERGY GAP IN SUPERCONDUCTORS YBaCuO, LaSrCuO AND BPBO

1987 ◽  
Vol 01 (02) ◽  
pp. 555-559 ◽  
Author(s):  
Hongjie TAO ◽  
Yingfei CHEN ◽  
Li LU ◽  
Qiansheng YANG ◽  
Bairu ZHAO ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Strong Coupling ◽  
Perovskite Structure ◽  
Energy Gap ◽  
Electron Tunneling ◽  
Point Contact ◽  
Tunneling Conductance ◽  
Temperature Ratio ◽  
Superconducting Energy Gap

We have carried out superconducting energy gap measurements for polycrystalline perovskite-structure superconductors YBaCuO, LaSrCuO and BPBO with point contact tunneling. The tunneling conductance curves for YBaCuO, LaSrCuO and BPBO show the energy gap to transition temperature ratio 2Δ/kTc =4.7, 7.8 and 5.05 respectively, which is consistant with the strong-coupling superconductivity.

scholarly journals A NOVEL MERON-INDUCED PSEUDOSPIN WAVE IN THE BILAYER QUANTUM HALL COHERENT STATE AND THE RESIDUAL ZERO-BIAS PEAK IN TUNNELING CONDUCTANCE

2003 ◽  
Vol 17 (26) ◽  
pp. 1377-1384
Author(s):  
YUE YU
Keyword(s):  
Coherent State ◽  
Bias Voltage ◽  
Rotational Symmetry ◽  
Quantum Hall ◽  
Tunneling Conductance ◽  
Zero Bias ◽  
Voltage Range ◽  
High Bias ◽  
Bilayer Quantum Hall ◽  
Periodic Domain Structure

In the bilayer quantum Hall coherent state for νT deviating slightly from unity, we show that, instead of the global order parameter, the periodic domain structure accompanying the charged meron pairs spontaneously breaks the pseudospin U(1) rotational symmetry. The motion of meron pairs induces a novel pseudospin wave. The long-range order of the periodic domains in a low bias voltage range leads to the residual zero-bias peak in the tunneling conductance, which can be distinct from the pseudopsin Goldstone feature in a high bias voltage range.

LOCAL ELECTRONIC PROPERTIES OF DOMAIN BOUNDARIES ON c(2 × 2) Fe(001) THIN FILM SURFACES

2006 ◽  
Vol 05 (06) ◽  
pp. 935-942 ◽  
Author(s):  
HIROFUMI OKA ◽  
AGUS SUBAGYO ◽  
KAZUHISA SUEOKA
Keyword(s):  
Bias Voltage ◽  
Surface States ◽  
Scanning Tunneling ◽  
Tunneling Conductance ◽  
Tunneling Microscopy ◽  
Voltage Range ◽  
Domain Boundaries ◽  
Voltage Dependent ◽  
The Difference

Scanning tunneling microscopy (STM) and spectroscopy have been performed on a nanostructure "line-like pattern" appearing on atomically flat terraces of bcc-Fe (001) with a c(2 × 2) reconstructed structure. Atomically resolved STM reveals that the line-like pattern consists of regularly aligned surface atoms that have a similar symmetry to the (1 × 1) structure of Fe (001). The line-like pattern plays a role of domain boundaries of c(2 × 2) domains. The patterns exhibit bias-voltage dependent image contrast in the STM topographic images. In negative sample bias-voltage range the patterns appear lower than the c(2 × 2) domains and higher in positive range. In dI/dV tunneling spectra taken on the patterns a shoulder is observed around +0.2 V. On the other hands, a small salient is distinguished around +0.4 V in the spectra taken on the c(2 × 2) domains. These features are originated from surface states existing on bcc-Fe (001) surfaces with (1 × 1) structure and c(2 × 2) reconstructed structure, respectively. Emergence of the line-like patterns results in the difference of tunneling conductance.

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