scholarly journals New refractory MAB phases and their 2D derivatives: insight into the effects of valence electron concentration and chemical composition

RSC Advances ◽  
2020 ◽  
Vol 10 (43) ◽  
pp. 25836-25847
Author(s):  
Yinqiao Liu ◽  
Zhou Jiang ◽  
Xue Jiang ◽  
Jijun Zhao
Keyword(s):  
Chemical Composition ◽  
Transition Metal ◽  
Electron Concentration ◽  
Valence Electron ◽  
Valence Electron Concentration ◽  
Group 13 ◽  
Insight Into

Since MAB (where M is a transition metal, A is a group 13–16 element, and B is boron) phases possess several useful properties, it is meaningful to develop a database to help us figure out optimal compositions and further promote their applications.

Electronic Structure of Ru2 Si3

1991 ◽  
Vol 234 ◽  
Author(s):  
P. Pecheur ◽  
G. Toussaint
Keyword(s):  
Electronic Structure ◽  
Transition Metal ◽  
Metal Atom ◽  
Electron Concentration ◽  
Valence Electron ◽  
Tight Binding ◽  
Transition Metal Atom ◽  
Valence Electron Concentration ◽  
Tight Binding Method ◽  
The Stability

ABSTRACTThe electronic structure of Ru2Si3 has been calculated with the empirical tight binding method and the recursion procedure. The calculation strongly indicates that there exists a gap in the structure, which makes Ru2Si3 semiconducting, as found experimentally and explains the stability of the chimney-ladder phases for a valence electron concentration per transition metal atom smaller than 14.

THE SIGNIFICANCE OF VALENCE ELECTRON CONCENTRATION ON THE FORMATION MECHANISM OF SOME TERNARY ALUMINUM-BASED QUASICRYSTALS

2002 ◽  
Vol 16 (31) ◽  
pp. 4665-4683 ◽  
Author(s):  
N. S. ATHANASIOU ◽  
C. POLITIS ◽  
J. C. SPIRLET ◽  
S. BASKOUTAS ◽  
V. KAPAKLIS
Keyword(s):  
Transition Metal ◽  
Formation Mechanism ◽  
Electron Concentration ◽  
Valence Electron ◽  
Composition Range ◽  
Atomic Radius ◽  
Atomic Ratio ◽  
Radius Ratio ◽  
Valence Electron Concentration ◽  
Stabilization Mechanism

In the present study we report on the formation mechanism of some binary Al-TM and ternary Al-Cu-TM (TM = transition metal) quasicrystals. We have found that the formation mechanism of quasicrystalline phases in the binary Al-TM system takes place at extremely high solidification rates, is linked to the location of the transition metal in the periodic table, depends upon the atomic radius ratio of the constituents, is composition sensitive, and as a result is strongly affected by the effective atomic radius ratio (a eff ). Applying empirical criteria on the formation of ternary Al-Cu-TM quasicrystals we were able to calculate the composition range at which the formation tendency and stability of quasicrystalline phases is enhanced. The method presented can be viewed as an empirical criterion to find new and high quality quasicrystalline materials and to optimize the quasicrystalline material composition. Furthermore, it was observed that the stabilization mechanism of the quasicrystalline Al-Cu-(Fe, Co, Ru, Rh, Os, Ir) phases takes place when the atomic ratio (TM+Cu)/Al ranges from 0.46 to 0.69 and for a eff values between 4.10 and 7.30. At the same valence electron concentration, metastable icosahedral Al-Cu-(Cr, Mn) phases are formed at relatively smaller atomic ratios (TM+Cu)/Al and having higher a eff values in comparison to those of the stable D- and I-phases.

3d transition-metal high-entropy Invar alloy developed by adjusting the valence-electron concentration

2021 ◽  
Vol 5 (4) ◽  
Author(s):  
Ziyuan Rao ◽  
Aslı Çakır ◽  
Özge Özgün ◽  
Dirk Ponge ◽  
Dierk Raabe ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electron Concentration ◽  
Valence Electron ◽  
Invar Alloy ◽  
Valence Electron Concentration ◽  
High Entropy

A New Condition of Formation and Stablity of All Crystalline Systems in a Good Agreement with Experimental Data

2015 ◽  
Vol 11 (3) ◽  
pp. 3224-3228
Author(s):  
Tarek El-Ashram
Keyword(s):  
Experimental Data ◽  
Brillouin Zone ◽  
Electron Concentration ◽  
Free Electron ◽  
Lattice Point ◽  
Valence Electron ◽  
Fermi Gas ◽  
Valence Electron Concentration ◽  
Fermi Sphere ◽  
Good Agreement

In this paper we derived a new condition of formation and stability of all crystalline systems and we checked its validity andit is found to be in a good agreement with experimental data. This condition is derived directly from the quantum conditionson the free electron Fermi gas inside the crystal. The new condition relates both the volume of Fermi sphere VF andvolume of Brillouin zone VB by the valence electron concentration VEC as ;𝑽𝑭𝑽𝑩= 𝒏𝑽𝑬𝑪𝟐for all crystalline systems (wheren is the number of atoms per lattice point).

scholarly journals Magnetic and Structural Transitions Tuned through Valence Electron Concentration in Magnetocaloric Mn(Co1–xNix)Ge

2018 ◽  
Vol 30 (4) ◽  
pp. 1324-1334 ◽  
Author(s):  
Qingyong Ren ◽  
Wayne D. Hutchison ◽  
Jianli Wang ◽  
Andrew J. Studer ◽  
Stewart J. Campbell
Keyword(s):  
Electron Concentration ◽  
Valence Electron ◽  
Valence Electron Concentration ◽  
Structural Transitions

Thermoelectric Properties of Ru2Si3-Based Chimney-Ladder Phases

2007 ◽  
Vol 561-565 ◽  
pp. 463-466 ◽  
Author(s):  
Kyosuke Kishida ◽  
Akira Ishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structures ◽  
Thermoelectric Properties ◽  
Electron Concentration ◽  
Valence Electron ◽  
Valence Electron Concentration ◽  
Compositional Range ◽  
Wide Compositional Range ◽  
P Type ◽  
Semiconducting Behavior

The variations of the crystal structures and thermoelectric properties of the Ru1-xRexSiy chimney-ladder phases were studied as a function of the Re concentration. A series of chimney-ladder phases with a compositional formula of Ru1-xRexSi1.539+0.178x are formed in a wide compositional range, 0.14 ≤ x ≤ 0.76. The composition of the chimney-ladder phase is systematically deviated from the idealized composition satisfying the valence electron concentration rule: VEC=14. Measurements of thermoelectric properties reveal that the chimney-ladder phases exhibit n-type semiconducting behavior at low Re concentrations and p-type semiconducting behavior at high Re concentrations, which are well consistent with the prediction based on the deviation of the composition of the chimney-ladder phase from the idealized composition.

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