Electronic Properties of Compact and Diluted Metal-Clusters by Impedance Spectroscopy

1992 ◽  
Vol 272 ◽  
Author(s):  
U. Simon ◽  
G. Schmid ◽  
G. Schön
Keyword(s):  
Electrical Conductivity ◽  
Impedance Spectroscopy ◽  
Density Of States ◽  
Metal Clusters ◽  
Optical Measurements ◽  
Metal Core ◽  
Quantum Size ◽  
Simple Quantum ◽  
Tunnel Conductivity ◽  
Cluster Properties

ABSTRACTAll presently published electrical and optical measurements on concentrated ligand stabilized Au55-cluster samples reveal an inter-cluster tunnel-conductivity and indicate the influence of a “quantum-size-effect” (QSE) [1],[2]. However these data do not show any initials for the separation of inter- and possible intracluster effects. In the present Raper electronic intra-cluster Properties such as the electrical “conductivity” of 1nm chemical auantum dots, their relaxation frequencies and the relevant activation enthalpies as well as the respective Properties of pairs of Au55-clusters have been investigated in comparison to diluted clusters and interpreted by means of Impedance Spectroscopy. Furthermore a method to determine the number and the density of states (DOS) in the metal-core from the measuring data by means of very simple quantum-size assumptions is presented, which is compatible with both the SIMIT[3] and the existing cluster models.

Production and STEM examination of controlled-size silver clusters

1983 ◽  
Vol 41 ◽  
pp. 338-339
Author(s):  
M. A. Listvan ◽  
R. P. Andres
Keyword(s):  
Cluster Size ◽  
Metal Clusters ◽  
Experimental Parameter ◽  
Carbon Films ◽  
Metal Species ◽  
Silver Clusters ◽  
Free Jet ◽  
Size Dependent ◽  
Cluster Properties ◽  
Controllable Size

Knowledge of the function and structure of small metal clusters is one goal of research in catalysis. One important experimental parameter is cluster size. Ideally, one would like to produce metal clusters of regulated size in order to characterize size-dependent cluster properties.A source has been developed which is capable of producing microscopic metal clusters of controllable size (in the range 5-500 atoms) This source, the Multiple Expansion Cluster Source, with a Free Jet Deceleration Filter (MECS/FJDF) operates as follows. The bulk metal is heated in an oven to give controlled concentrations of monomer and dimer which were expanded sonically. These metal species were quenched and condensed in He and filtered to produce areosol particles of a controlled size as verified by mass spectrometer measurements. The clusters were caught on pre-mounted, clean carbon films. The grids were then transferred in air for microscopic examination. MECS/FJDF was used to produce two different sizes of silver clusters for this study: nominally Ag6 and Ag50.

Effect of Interconnectivity of Nickel on Electrical and Thermal Properties of Alumina-Ni Interpenetrating Phase Composite

2011 ◽  
Vol 239-242 ◽  
pp. 2679-2682 ◽  
Author(s):  
Rub Nawaz Shahid ◽  
Bin Awais Hasan ◽  
Fahad Ali ◽  
Naeem Ul Haq Tariq
Keyword(s):  
Electrical Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Impedance Spectroscopy ◽  
Electron Spectroscopy ◽  
Coefficient Of Thermal Expansion ◽  
Optimal Combination ◽  
Percolation Limit ◽  
Scanning Electron

In this work percolation range for Al2O3-Ni interpenetrating phase composite (IPC) was studied to find the optimal combination of electrical conductivity and coefficient of thermal expansion (CTE). The impedance spectroscopy and scanning electron spectroscopy were used to study the percolation limit.

scholarly journals Effect of band structure adjustment based of Cu site on the thermoelectric properties of BiCuSeO

2021 ◽  
Author(s):  
Bo Feng
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Effective Mass ◽  
Valence Band ◽  
Thermoelectric Properties ◽  
Density Of States ◽  
First Principles Calculation ◽  
Temperature Range ◽  
Ti Doping

Abstract The effect of Ti doped at Cu site on the thermoelectric properties of BiCuSeO was studied by experimental method and first principles calculation. The results show that Ti doping can cause the lattice contraction and decrease the lattice constant. Ti doping can increase the band gap and lengthen the Cu/Ti-Se bond, resulting in the decrease of carrier concentration. Ti doping can reduce the effective mass and the Bi-Se bond length, correspondingly improve the carrier mobility. Ti doping can decrease the density of states of Cu-3d and Se-4p orbitals at the top of valence band, but Ti-4p orbitals can obviously increase the density of states at the top of valence band and finally increase the electrical conductivity in the whole temperature range. With the decrease of effective mass, Ti doping would reduce the Seebeck coefficient, but the gain effect caused by the increase of electrical conductivity is more than the benefit reduction effect caused by the decrease of Seebeck coefficient, and the power factor shows an upward trend. Ti doping can reduce Young's modulus, lead to the increase of defect scattering and strain field, correspondingly reduce the lattice thermal conductivity and total thermal conductivity. It is greatly increased for the ZT values in the middle and high temperature range, with the highest value of 1.04 at 873 K.

The Study of Charge Transport in Nanoscale DNA Structures

2010 ◽  
Vol 1280 ◽  
Author(s):  
G. Bart ◽  
M. R. Singh ◽  
M. Zinke-Allamang
Keyword(s):  
Electrical Conductivity ◽  
Density Of States ◽  
Variable Range Hopping ◽  
Band Tail ◽  
Phonon Interaction ◽  
Dna Structures ◽  
Electron Phonon Interaction ◽  
Electric Field Dependence ◽  
Exponential Density ◽  
Base Distance

AbstractWe have studied the variable range hopping (VRH) mechanism for polarons in DNA structures using an exponential density of states. Due to the electron-phonon interaction localized polarons are formed in the DNA helix. The unwinding of DNA increases molecular orbital overlap between bases while decreasing the base-to-base distance. These types of vibrations create phonons. We consider that DNA has a band tail which has an exponential density of states and we have calculated the temperature- and the electric field dependence of the conductivity. We compare our model with the experiments of the electrical conductivity of samples of double-stranded H5N1 genes of avian Influenza virus DNA. Our theory is able to explain their data.

The effect of indium doping on structural, electrical conductivity, photoconductivity and density of states properties of ZnO films

2010 ◽  
Vol 490 (1-2) ◽  
pp. 62-67 ◽  
Author(s):  
C.E. Benouis ◽  
M. Benhaliliba ◽  
A. Sanchez Juarez ◽  
M.S. Aida ◽  
F. Chami ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Density Of States ◽  
Zno Films ◽  
Indium Doping

Role of Quantum-size Effects on the Dehydrogenation of CH4 on 3d TMn Clusters: DFT Calculations Combined with Data Mining

2022 ◽  
Author(s):  
Karla Furtado Andriani ◽  
Priscilla Felício Sousa ◽  
Felipe Orlando Morais ◽  
Juarez L. F. Da Silva
Keyword(s):  
Data Mining ◽  
Transition Metal ◽  
Dft Calculations ◽  
Theoretical Investigation ◽  
Size Effects ◽  
Metal Clusters ◽  
Quantum Size Effects ◽  
Transition Metal Clusters ◽  
Quantum Size

In this work, we report a theoretical investigation of the role of quantum-size effects (QSE) on the dehydrogenation of methane (CH4) on 3d transition-metal clusters, TMn , where TM =...

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