Structural and Mechanical Properties of Boron Nanotubes

2003 ◽  
Vol 791 ◽  
Author(s):  
Matthew H. Evans ◽  
John D. Joannopoulos ◽  
Sokrates T. Pantelides
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Ground State ◽  
First Principles ◽  
Elastic Response ◽  
Unusual Property ◽  
First Principles Calculations ◽  
Ground State Degeneracy ◽  
Cohesive Energies ◽  
Novel Structures

ABSTRACTWe report the results of first-principles calculations showing that boron can form a wide variety of metastable planar and tubular forms with unusual electronic and mechanical properties. The preferred planar structure is a buckled triangular lattice that breaks the threefold ground state degeneracy of the flat triangular plane. When the plane is rolled into a tube, the ground state degeneracy leads to a strong chirality dependence of the binding energy and elastic response, an unusual property that is not found in carbon nanotubes. The achiral (n, 0) tubes derive their structure from the flat triangular plane. The achiral (n, n) boron nanotubes arise from the buckled plane, and have large cohesive energies and novel structures as a result.

Structural, Electronic, Elastic and Mechanical Properties of ScNi, ScPd and ScPt: A FP-LAPW Study

2014 ◽  
Vol 1047 ◽  
pp. 27-34 ◽  
Author(s):  
Bushra Fatima ◽  
Sunil Singh Chouhan ◽  
Nikita Acharya ◽  
S.P. Sanyal
Keyword(s):  
Mechanical Properties ◽  
Band Structure ◽  
Bulk Modulus ◽  
Ground State ◽  
First Principles ◽  
First Principles Calculations ◽  
Fermi Surfaces ◽  
First Order ◽  
Cauchy Pressure ◽  
Metallic Bonding

Systematic first principles calculations have been carried out to study the structural, electronic, elastic and mechanical properties of ScNi, ScPd and ScPt using FP-LAPW method within GGA. The ground state properties such as lattice constant, bulk modulus and first order pressure derivates of bulk modulus, were evaluated. The electronic and bonding patterns of these compounds have been analysed quantitatively from band structure and Fermi surfaces. It is clear from band structures that these compounds are metallic in nature. Ductility for these compounds is analysed by using Pugh’s criteria, Cauchy pressure (C12–C44) and Frantsevich rule. Amongst all these Sc compounds, ScNi is found to be most ductile due to the presence of strong metallic bonding.

Computational materials discovery: the case of the W–B system

2014 ◽  
Vol 70 (2) ◽  
pp. 85-103 ◽  
Author(s):  
Xi-Yue Cheng ◽  
Xing-Qiu Chen ◽  
Dian-Zhong Li ◽  
Yi-Yi Li
Keyword(s):  
Mechanical Properties ◽  
Ground State ◽  
First Principles ◽  
Measured Data ◽  
First Principles Calculations ◽  
Stable Compound ◽  
Current State ◽  
Computational Materials ◽  
State Of Research ◽  
Good Agreement

By means of variable-compositional evolutionary algorithms, in combination with first-principles calculations, the compositions, structures and mechanical properties of the W–B system have been theoretically investigated. As well as confirming the experimental observations (including their crystal structures) for the four known compounds W2B, WB, WB2and WB3, the new stable compound W8B7and two nearly stable compounds, W2B3and WB4, have also been predicted in the ground state. The elastic properties and estimated Vickers hardnesses of all these borides have been systematically derived. The results show that, among these borides,hP6-WB2exhibits the largest ultra-incompressibility along thecaxis, with the highestC33value (953 GPa, comparable with that of the most incompressible diamond).hP16-WB3exhibits the highest hardness of 36.9 GPa, in good agreement with the experimentally measured data from 28.1 to 43.3 GPa, close to the superhard threshold, andoC8-WB shows the highest bulk modulus of about 350 GPa. The new stable compound W8B7crystallizes in the monoclinicmP15 phase, with infinite zigzag B chains running parallel to the W-atom layers, resulting in a relatively high estimated hardness of 19.6 GPa. The anisotropic Young's modulusEand torsion shear modulusGthave been derived for bothoC8-WB andhP16-WB3. The current state of research and the historic inconsistency of the W–B system are briefly summarized, in particular clarifying the fact that the previous experimentally attributedhP20-WB4is in fact the defect-containinghP16-WB3.

The structural, elastic and thermodynamic properties of intermetallic phases in Mg–Sn–Si–Ca(Sr) alloys: A first-principles study

2018 ◽  
Vol 32 (22) ◽  
pp. 1850246
Author(s):  
Yan Li ◽  
Yuhong Zhao ◽  
Hua Hou ◽  
Xiaomin Yang
Keyword(s):  
Mechanical Properties ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Poisson Ratio ◽  
Debye Model ◽  
Intermetallic Phases ◽  
First Principles Calculations ◽  
Formation Enthalpies ◽  
Anisotropy Index ◽  
Cohesive Energies

The structural, elastic and thermodynamic properties of Mg2Si, Mg2Sn, CaMgSi and MgSnSr phases in Mg–Sn–Si–Ca(Sr) alloys have been investigated by implementing first-principles calculations. Formation enthalpies and cohesive energies show that MgSnSr has the strongest alloying ability and CaMgSi has the highest structural stability. The bulk modulus B, shear modulus G, Young’s modulus E, G/B, Poisson ratio [Formula: see text], anisotropy index A[Formula: see text] are estimated after evaluating the elastic constants. The mechanical properties are further analyzed and discussed. Finally, the Gibbs free energy and Debye temperature of these phases are calculated by means of the quasi-harmonic Debye model in temperature ranging from 0 K to 1000 K.

Investigation of the transport, structural and mechanical properties of half-metallic REMnO3 (RE = Ce and Pr) ferromagnets

RSC Advances ◽  
2016 ◽  
Vol 6 (100) ◽  
pp. 97641-97649 ◽  
Author(s):  
Shakeel Ahmad Khandy ◽  
Dinesh C. Gupta
Keyword(s):  
Mechanical Properties ◽  
Ground State ◽  
First Principles ◽  
Perovskite Oxides ◽  
Systematic Investigation ◽  
Ground State Structure ◽  
First Principles Calculations ◽  
State Structure ◽  
Half Metallicity ◽  
Half Metallic

Systematic investigation of the ground state structure, elastic and transport properties, of perovskite oxides REMnO3 (RE = Ce and Pr) has been carried out by first principles calculations. The half-metallicity and ferromagnetism is well explained.

scholarly journals Structural and physical properties of 99 complex bulk chalcogenides crystals using first-principles calculations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sahib Hasan ◽  
Khagendra Baral ◽  
Neng Li ◽  
Wai-Yim Ching
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
First Principles ◽  
Experimental Studies ◽  
First Principles Calculations ◽  
Chalcogenide Semiconductors ◽  
Optical And Mechanical Properties ◽  
Very Large Database ◽  
Unique Composition ◽  
Fundamental Physical

AbstractChalcogenide semiconductors and glasses have many applications in the civil and military fields, especially in relation to their electronic, optical and mechanical properties for energy conversion and in enviormental materials. However, they are much less systemically studied and their fundamental physical properties for a large class chalcogenide semiconductors are rather scattered and incomplete. Here, we present a detailed study using well defined first-principles calculations on the electronic structure, interatomic bonding, optical, and mechanical properties for 99 bulk chalcogenides including thirteen of these crytals which have never been calculated. Due to their unique composition and structures, these 99 bulk chalcogenides are divided into two main groups. The first group contains 54 quaternary crystals with the structure composition (A2BCQ4) (A = Ag, Cu; B = Zn, Cd, Hg, Mg, Sr, Ba; C = Si, Ge, Sn; Q = S, Se, Te), while the second group contains scattered ternary and quaternary chalcogenide crystals with a more diverse composition (AxByCzQn) (A = Ag, Cu, Ba, Cs, Li, Tl, K, Lu, Sr; B = Zn, Cd, Hg, Al, Ga, In, P, As, La, Lu, Pb, Cu, Ag; C = Si, Ge, Sn, As, Sb, Bi, Zr, Hf, Ga, In; Q = S, Se, Te; $$\hbox {x} = 1$$ x = 1 , 2, 3; $$\hbox {y} = 0$$ y = 0 , 1, 2, 5; $$\hbox {z} = 0$$ z = 0 , 1, 2 and $$\hbox {n} = 3$$ n = 3 , 4, 5, 6, 9). Moreover, the total bond order density (TBOD) is used as a single quantum mechanical metric to characterize the internal cohesion of these crystals enabling us to correlate them with the calculated properties, especially their mechanical properties. This work provides a very large database for bulk chalcogenides crucial for the future theoretical and experimental studies, opening opportunities for study the properties and potential application of a wide variety of chalcogenides.

scholarly journals First principles calculations of the structural, electronic, magnetic, and thermodynamic properties of the Nd2MgGe2 and Gd2MgGe2 intermetallic compounds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Menouer ◽  
O. Miloud Abid ◽  
A. Benzair ◽  
A. Yakoubi ◽  
H. Khachai ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermodynamic Properties ◽  
Ground State ◽  
First Principles ◽  
Essential Role ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Rare Earth Compounds ◽  
First Principles Calculations ◽  
Antiferromagnetic Ground State

AbstractIn recent years the intermetallic ternary RE2MgGe2 (RE = rare earth) compounds attract interest in a variety of technological areas. We therefore investigate in the present work the structural, electronic, magnetic, and thermodynamic properties of Nd2MgGe2 and Gd2MgGe2. Spin–orbit coupling is found to play an essential role in realizing the antiferromagnetic ground state observed in experiments. Both materials show metallicity and application of a Debye-Slater model demonstrates low thermal conductivity and little effects of the RE atom on the thermodynamic behavior.

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