scholarly journals First Principles Study of Electronic Structure and Magnetic Properties of TMH (TM = Cr, Mn, Fe, Co)

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
S. Kanagaprabha ◽  
R. Rajeswarapalanichamy ◽  
K. Iyakutti
Keyword(s):  
Phase Transition ◽  
Magnetic Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Local Density ◽  
Hexagonal Phase ◽  
Structural Phase ◽  
Tight Binding ◽  
Transition Metal Hydrides ◽  
Lmto Method

First principles calculations are performed using a tight-binding linear muffin-tin orbital (TB-LMTO) method with local density approximation (LDA) and atomic sphere approximation (ASA) to understand the electronic properties of transition metal hydrides (TMH) (TM = Cr, Mn, Fe, Co). The structural property, electronic structure, and magnetic properties are investigated. A pressure induced structural phase transition from cubic to hexagonal phase is predicted at the pressures of 50 GPa for CrH and 23 GPa for CoH. Also, magnetic phase transition is observed in FeH and CoH at the pressures of 10 GPa and 180 GPa, respectively.

Ab Initio Study of Structural Phase Transition and Electronic Properties in Samarium (Sm) Compounds

2016 ◽  
Vol 1141 ◽  
pp. 184-189
Author(s):  
Yeshvir Singh Panwar ◽  
Mahendra Aynyas ◽  
Jagdeesh Pataiya ◽  
Sankar P. Sanyal
Keyword(s):  
Phase Transition ◽  
Bulk Modulus ◽  
Structural Phase Transition ◽  
Local Density ◽  
Structural Phase ◽  
Tight Binding ◽  
Energy Band Diagram ◽  
Lattice Parameter ◽  
Type B ◽  
Lmto Method

The electronic structure and high pressure structural phase transition of SmTe and SmPo have been studied by using tight binding linear muffin-tin-orbital (TB-LMTO) method within the local density approximation (LDA). The total energy as a function of volume is obtained and it is found that these compounds are stable in NaCl-type (B1-phase) structure and transform to CsCl-type (B2-type) structure. The transition pressure of SmTe and SmPo are found to be 6.6 GPa and 8.6 GPa respectively. We have also calculated lattice parameter (a0), bulk modulus (B0), band structure (BS) and density of states (DOS). From energy band diagram, we observed that these compounds exhibit weakly metallic behaviour. The calculated values of lattice parameter and bulk modulus agree well with the available data.

Magnetic Properties of Embedded Rh Clusters in Ni Matrix

1995 ◽  
Vol 384 ◽  
Author(s):  
Zhi-Qiang Li ◽  
Yuichi Hashi ◽  
Jing-Zhi Yu ◽  
Kaoru Ohno ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Magnetic Moments ◽  
Functional Formalism ◽  
Rhodium Clusters ◽  
Spin Polarized ◽  
Local Density Functional

ABSTRACTThe electronic structure and magnetic properties of rhodium clusters with sizes of 1 - 43 atoms embedded in the nickel host are studied by the first-principles spin-polarized calculations within the local density functional formalism. Single Rh atom in Ni matrix is found to have magnetic moment of 0.45μB. Rh13 and Rhl 9 clusters in Ni matrix have lower magnetic moments compared with the free ones. The most interesting finding is tha.t Rh43 cluster, which is bulk-like nonmagnetic in vacuum, becomes ferromagnetic when embedded in the nickel host.

Structural Phase Stability of ThSb Under Pressure

1994 ◽  
Vol 364 ◽  
Author(s):  
B. Palanivel ◽  
G. Kalpana ◽  
M. Rajagopalan
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Cell Volume ◽  
Structural Transition ◽  
Structural Phase ◽  
Tight Binding ◽  
Lmto Method ◽  
Cscl Structure ◽  
Total Energies ◽  
Good Agreement

AbstractThe electronic structure and high pressure structural phase transition in thorium antimonide have been investigated using the tight binding LMTO method. We have calculated the total energies by reducing the cell volume for NaCl as well as CsCl structures using TBLMTO method. The total energy calculations reveal that ThSb undergoes a structural transition from NaCl to CsCl structure at 78 kbar. The calculated value of equilibrium cell volume and the cell volume at which phase transition occurs are found to have a good agreement with the experimental results.

Structural Phase Transition and Electronic Properties of MgCe under High Pressure from First-Principles Calculations

2014 ◽  
Vol 577 ◽  
pp. 102-107
Author(s):  
Qiu Xiang Liu ◽  
De Ping Lu ◽  
Rui Jun Zhang ◽  
Lei Lu ◽  
Shi Fang Xie
Keyword(s):  
Phase Transition ◽  
Ground State ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
High Pressures ◽  
Local Density ◽  
Structural Phase ◽  
First Principles Calculations ◽  
Functional Theory

The structural stability of MgCe under high pressures has been investigated by using the first-principles plane-wave pseudopotential density functional theory within the local density approximation (LDA). The obtained results predict that MgCe in the Ba structure is predicted to be the most stable structure corresponding to the ground state, because of lowest total energy. MgCe undergoes a pressure-induced phase transition from the Ba structure to B32 structure at 36 GPa. And no further transition is found up to 120 GPa. In addition, the electronic structures of four structures of MgCe are also calculated and discussed.

Structural and Electronic Properties of Thulium Compounds

2016 ◽  
Vol 28 ◽  
pp. 59-64
Author(s):  
Yeshvir Singh Panwar ◽  
Mahendra Aynyas ◽  
Jagdeesh Pataiya ◽  
Sankar P. Sanyal
Keyword(s):  
Bulk Modulus ◽  
Local Density ◽  
Structural Phase ◽  
Tight Binding ◽  
Energy Band Diagram ◽  
Lattice Parameter ◽  
Band Diagram ◽  
Cscl Type ◽  
Structural And Electronic Properties ◽  
Lmto Method

The tight binding linear muffin-tin-orbital (TB-LMTO) method within the local density approximation (LDA) is used to study the electronic structure and high pressure behaviour of thulium compounds TmX (X= P, As, S, and Se). We also predict a structural phase transition from NaCl to CsCl-type structure. The transition pressures were found to be 40.0, 31.0, 58.0 and 49.0 GPa, for TmP, TmAs, TmS and TmSe respectively. Apart from this, the lattice parameter (a0), bulk modulus (B0), band structure and density of states are calculated. From energy band diagram, it is observed that these compounds exhibit weak metallic character. The calculated values of lattice parameters and bulk modulus are of reasonable agreement with available data.

Pressure-induced Structural Phase Transition of Carbon Nanotubes into New Nanostructured Carbon Solids

2009 ◽  
Vol 1204 ◽  
Author(s):  
Masahiro Sakurai ◽  
Susumu Saito
Keyword(s):  
Phase Transition ◽  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Structural Phase Transition ◽  
Density Functional ◽  
Local Density ◽  
Structural Phase ◽  
Tight Binding ◽  
Dynamics Simulation ◽  
Nanotube Bundles

AbstractWe study pressure-induced structural phase transition of carbon nanotubes using the constant-pressure tight-binding molecular-dynamics simulation. The systems studied are nanotube bundles composed of (6,6) armchair nanotube and/or (7,4) chiral nanotube, which are reported to be the nanotubes relatively abundant in experimentally purified sample. We find that the nanotube bundles transforms into a new phase that consist of graphitic ribbons and diamond blocks, “graphitic nanoribbon solid”. It is also found that sp3-rich phases obtained from the armchair nanotubes possess an anisotropic network and have high hardness which is comparable to that of cubic diamond. In the case of the bundles containing chiral nanotubes, on the other hand, amorphous diamond phase is obtained. Based on the local-density approximation in the density-functional theory, we also investigate the energetics and electronic structure of some of new carbon phases obtained in the molecular-dynamics study.

Ground State and Electronic Properties of Americium (Am) Compounds

2016 ◽  
Vol 1141 ◽  
pp. 176-179
Author(s):  
Jagdeesh Pataiya ◽  
Mahendra Aynyas ◽  
Chandrabhan Makode ◽  
Sankar P. Sanyal
Keyword(s):  
Electronic Properties ◽  
Ground State ◽  
Local Density ◽  
Ambient Pressure ◽  
Structural Phase ◽  
Tight Binding ◽  
Type Structure ◽  
Cscl Type ◽  
Lmto Method ◽  
First Time

The ground state and electronic properties of americium pnictides (AmY, Y=N, P) has been calculated with the help of tight binding linear muffin-in-orbital (TB-LMTO) method within the local density approximation (LDA). From present study it is found that AmN and AmP are stable in NaCl – type structure under ambient pressure. The structural stability of AmN and AmP changes under the application of pressure. We predict a structural phase transition from NaCl-type to CsCl-type structure for these Am-pnictides in the pressure range of 36.0 – 47.0 GPa (AmN-AmP). Optimized lattice parameters, transition pressures and bulk modulus were obtained for the first time and analyzed in comparison with the available theoretical and experimental data.

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