Defect Generation in Some Transition-Metal Silicides in Accommodating the Deviation from the Stoichiometric Compositions

2007 ◽  
Vol 561-565 ◽  
pp. 443-446 ◽  
Author(s):  
Haruyuki Inui ◽  
Katsushi Tanaka ◽  
Kyosuke Kishida ◽  
S. Harada
Keyword(s):  
Transition Metal ◽  
Valence Electron ◽  
Vacancy Concentration ◽  
Relative Magnitude ◽  
Defect Structures ◽  
Defect Engineering ◽  
Electron Number ◽  
Counting Rule ◽  
Metal Silicides ◽  
Ternary Alloying

The changes in microstructure and defect structure of two different semiconducting transition-metal silicides, ReSi1.75 and Ru2Si3 with ternary alloying of substitutional elements with a valence electron number different from that of the constituent metal have been investigated in order to see if the crystal and defect structures of these silicides and thereby their physical properties can be controlled through defect engineering according to the valence electron counting rule. The Si vacancy concentration and its arrangement can be successfully controlled in ReSi1.75 while the relative magnitude of the metal and silicon subcell dimensions in the chimney-ladder structures can be successfully controlled in Ru2Si3.

Defect Control and Defect Engineering of Transition-metal Silicides

2006 ◽  
Vol 980 ◽  
Author(s):  
Haruyuki Inui ◽  
Katsushi Tanaka ◽  
Kyosuke Kishida
Keyword(s):  
Transition Metal ◽  
Thermoelectric Properties ◽  
Valence Electron ◽  
Vacancy Concentration ◽  
Relative Magnitude ◽  
Defect Engineering ◽  
Counting Rule ◽  
Substitutional Element ◽  
Metal Silicides ◽  
Defect Control

AbstractThe microstructure, defect structure and thermoelectric properties of two different semiconducting transition-metal silicides, ReSi1.75 and Ru2Si3 upon alloying with a substitutional element with a valence electron number different from that of the constituent metal have been investigated in order to see if the crystal and defect structures of these silicides and thereby their physical properties can be controlled through defect engineering according to the valence electron counting rule. The Si vacancy concentration and its arrangement can be successfully controlled in ReSi1.75 while the relative magnitude of the metal and silicon subcell dimensions in the chimney-ladder structures can be successfully controlled in Ru2Si3. As a result, the improvement in the thermoelectric properties and the p- to n-type conduction transition are successfully achieved respectively for these semiconducting transition-metal silicides.

Ferromagnetic Dirac Half-Metallicity in Transition Metal Embedded Honeycomb Borophene

2021 ◽  
Author(s):  
Yanxia Wang ◽  
Xue Jiang ◽  
Yi Wang ◽  
Jijun Zhao
Keyword(s):  
Transition Metal ◽  
First Principles ◽  
Valence Electron ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Next Generation ◽  
Half Metallicity ◽  
Counting Rule ◽  
Spintronic Devices ◽  
Electron Counting

Exploring two-dimensional (2D) ferromagnetic materials with intrinsic Dirac half-metallicity is crucial for the development of next-generation spintronic devices. Based on first-principles calculations, here we propose a simple valence electron-counting rule...

Defect engineering and characterization of active sites for efficient electrocatalysis

Nanoscale ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 3327-3345
Author(s):  
Xuecheng Yan ◽  
Linzhou Zhuang ◽  
Zhonghua Zhu ◽  
Xiangdong Yao
Keyword(s):  
Transition Metal ◽  
Active Sites ◽  
Defect Engineering ◽  
Metal Free

This review highlights recent advancements in defect engineering and characterization of both metal-free carbons and transition metal-based electrocatalysts.

Synergistic vacancy defects and mechanical strain for the modulation of the mechanical, electronic and optical properties of monolayer tungsten disulfide

2021 ◽  
Vol 23 (10) ◽  
pp. 6298-6308
Author(s):  
Chan Gao ◽  
Xiaoyong Yang ◽  
Ming Jiang ◽  
Lixin Chen ◽  
Zhiwen Chen ◽  
...  
Keyword(s):  
Optical Properties ◽  
Transition Metal ◽  
Mechanical Strain ◽  
Transition Metal Dichalcogenides ◽  
Strain Engineering ◽  
Tungsten Disulfide ◽  
Defect Engineering ◽  
Vacancy Defects ◽  
Electronic And Optical Properties ◽  
Metal Dichalcogenides

The combination of defect engineering and strain engineering for the modulation of the mechanical, electronic and optical properties of monolayer transition metal dichalcogenides (TMDs).

scholarly journals The Categorization and Structural Prediction of Transition Metal Carbonyl Clusters Using 14n Series Numerical Matrix

2016 ◽  
Vol 8 (1) ◽  
pp. 109
Author(s):  
Enos Masheija Rwantale Kiremire
Keyword(s):  
Transition Metal ◽  
Valence Electron ◽  
Metal Carbonyl ◽  
Electron Content ◽  
Constant Number ◽  
Carbonyl Clusters ◽  
Structural Prediction ◽  
Metal Carbonyl Clusters ◽  
The Matrix ◽  
Special Case

<p>A matrix table of valence electron content of carbonyl clusters has been created using the 14n-based series. The numbers so generated form an array of series which conform precisely with valence electron contents of carbonyl clusters. The renowned 18 electron rule is a special case of 14n+4 series. Similarly, the 16 electron rule is another special case of the 14n+2 series. Categorization of the carbonyl clusters using the matrix table of series has been demonstrated. The table is so organized that clusters numerically represented can easily be compared and analyzed. The numbers that are diagonally arranged from right to left represent capping series. The row from right to left represents a decrease in valence electron content with increase in cluster linkages. The variation of cluster shapes of constant number of skeletal elements especially four or more may be monitored or compared with the variation with the valence electron content.</p>

scholarly journals Structural simplicity and complexity of compressed calcium: electronic origin

2014 ◽  
Vol 70 (3) ◽  
pp. 423-428 ◽  
Author(s):  
Valentina F. Degtyareva
Keyword(s):  
Valence Electron ◽  
Interaction Model ◽  
Outer Core ◽  
Electron Number ◽  
Fermi Sphere ◽  
Simple Cubic ◽  
Valence Electrons ◽  
Cubic Structure ◽  
Structural Simplicity ◽  
Tetragonal Cell

A simple cubic structure with one atom in the unit cell found in compressed calcium is counterintuitive to the traditional view of a tendency towards densely packed structures with an increase in pressure. To understand this unusual transformation it is necessary to assume electron transfer from the outer core band to the valence band, and an increase of valence electron number for calcium from 2 to ∼ 3.5. This assumption is supported by the Fermi sphere–Brillouin zone interaction model that increases under compression. The recently found structure of Ca-VII with a tetragonal cell containing 32 atoms (tI32) is similar to that in the intermetallic compound In5Bi3with 3.75 valence electrons per atom. Structural relations are analyzed in terms of electronic structure resemblance. Correlations of structure and physical properties of Ca are discussed.

scholarly journals Robust trap effect in transition metal dichalcogenides for advanced multifunctional devices

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Lei Yin ◽  
Peng He ◽  
Ruiqing Cheng ◽  
Feng Wang ◽  
Fengmei Wang ◽  
...  
Keyword(s):  
Transition Metal ◽  
High Performance ◽  
Infrared Detector ◽  
Transition Metal Dichalcogenides ◽  
Two Dimensional ◽  
Electric Transport ◽  
Defect Engineering ◽  
Fast Switching ◽  
Metal Dichalcogenides ◽  
Poor Stability

Abstract Defects play a crucial role in determining electric transport properties of two-dimensional transition metal dichalcogenides. In particular, defect-induced deep traps have been demonstrated to possess the ability to capture carriers. However, due to their poor stability and controllability, most studies focus on eliminating this trap effect, and little consideration was devoted to the applications of their inherent capabilities on electronics. Here, we report the realization of robust trap effect, which can capture carriers and store them steadily, in two-dimensional MoS2xSe2(1-x) via synergistic effect of sulphur vacancies and isoelectronic selenium atoms. As a result, infrared detection with very high photoresponsivity (2.4 × 105 A W−1) and photoswitching ratio (~108), as well as nonvolatile infrared memory with high program/erase ratio (~108) and fast switching time, are achieved just based on an individual flake. This demonstration of defect engineering opens up an avenue for achieving high-performance infrared detector and memory.

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